


















































PHYSIOLOGY AND HYGIENE 






A modern fairy developing grace, beauty and health 





HYGIENE AND HEALTH SERIES 


Physiology and Hygiene 

BOOK TWO 


By 

CHARLES P. EMERSON 

Dean and Professor of Medicine, Indiana University 
School of Medicine 

and 

GEORGE HERBERT BETTS 

Northwestern University, Evanston, Illinois 



Illustrated 


INDIANAPOLIS 

THE BOBBS-MERRILL COMPANY 
PUBLISHERS 



Copyright 1920, 1921 
The Bobbs-Merrill Company 


£55 



HUG-1'21 

©CU617807 






INTRODUCTION 


The dominant aim of this volume, as of Book One of Hy¬ 
giene and Health, is to make the instruction carry immediately 
over into practise. Many important facts and principles are 
presented, but never as an end in themselves. At every point 
the plans are laid and lessons organized to make it easy for 
pupils to live the hygienic truths learned and for teachers to 
help them secure this result. 

It follows from this statement that emphasis on hygiene is 
strong in the present text, as it was in Book One. In this vol¬ 
ume, however, the hygienic element is more definitely related 
to physiological function and to anatomical structure in order 
that the pupil may more fully understand the laws and prin¬ 
ciples which govern right physical living. 

An attempt has been made to approach each topic on the 
plane of the pupil’s interests and physical needs. Scientific 
truths are stated in simple language without technicalities. The 
exercises and problems assigned are adapted to the age and un¬ 
derstanding. The experiments suggested and investigations 
asked for are such as can be carried out in any school or home. 
The applications made are definite and practical and have a 
direct bearing on health and growth. The whole treatment seeks 
to stimulate interest and pride in clean, well-formed, healthy 
bodies, trained to skilful uses. 

Teachers will appreciate the effort to make the text teachable 
as well as learnable. Points of major importance are set out by 
numbered and indented paragraphs, or by other devices which 
make clear assignment easy and careful testing of results possi¬ 
ble. Besides the thought problems and simple experiments 
found in connection with nearly every lesson, questions are 
appended to each chapter on the facts contained in the text of 
the chapter. 

This volume will have accomplished its purpose if it in some 
degree helps advance the effort to make our schools an effective 
instrument for raising the general level of health and increasing 
the physical efficiency of our people. 

The Authors. 


ACKNOWLEDGMENTS 


Acknowledgments are due and gratefully rendered 
the following organizations and persons for permission 
to use photographs supplied by them: Boston Y. M. 
C. A., for pictures appearing on pages 2, 5, 15, 52, 77, 
221, 289; Boy Scouts of America, for pictures appearing 
on pages 19,22,49,66, no, 152, 158,221,244,245,303; 
Boston public schools, for pictures appearing on pages 
3, 9; National Girl Scouts for pictures appearing on 
pages 33, 128; United States Department of Agricul¬ 
ture, for pictures appearing on pages 130, 212; 
National Tuberculosis Association, for the picture ap¬ 
pearing on page 72; A. B. Saunders Company, for 
pictures appearing on pages 192, 195; and O. A. Morris 
for pictures appearing on pages 299, 305. 


The Authors. 


CONTENTS 


I 

The Body in Action 


i 

II 

The Muscles at Work 


ii 

III 

Training the Muscles 


18 

IV 

The Framework of the Body 


26 

V 

Joints and Body Movements 


36 

VI 

The Foot and Its Care 



VII 

How the Body is Controlled 


48 

VIII 

Brain and Nerves .... 


55 

IX 

The Nerve Cells and Fibers 


62 

X 

The Nervous System at Work 


. 68 

XI 

Getting Rid of Fatigue . 


75 

XII 

The Blood and Its Work 


82 

XIII 

The Circulation of the Blood 


89 

XIV 

Blood and Lymph .... 


100 

XV 

Breathing ..... 



XVI 

The Work of the Lungs . . 


116 

XVII 

Nature’s Food Laboratories 


• 125 

XVIII 

Kinds of Food Required . 


• 133 

XIX 

Measuring Food Values . 


. 141 

XX 

Why We Cook Our Food . 


• 149 

XXI 

Water as Food. 


• 155 

XXII 

Where Digestion Takes Place 

* 

164 

XXIII 

The Work of the Teeth . 


. 172 

XXIV 

Glands and Their Work . 


. 184 

XXV 

The Wonderful Body . 


. 191 

XXVI 

Disease Germs and Sickness 


198 

XXVII 

Guarding against Disease 


207 

XXVIII 

The Body’s Defenses . 


215 

XXIX 

Vaccination and the Prevention of 



Disease. 225 









CONTENTS 


CHAPTER PAGE 

XXX Community Cooperation and Health . .232 

XXXI Making Sure against Tuberculosis . . 241 

XXXII Protection against Other Common 

Diseases. 247 

XXXIII The Senses. 254 

XXXIV Good Eyes. 261 

XXXV Good Ears. 269 

XXXVI The Case against Alcohol .277 

XXXVII The Case against Tobacco. 285 

XXXVIII In the Sick Room.292 

XXXIX Keeping Cool in Emergencies .... 297 

XL What to Do in Emergencies .... 302 

XLI Safety First. 313 

Glossary. . . 317 

Index.320 











PHYSIOLOGY AND HYGIENE 


DAILY HEALTH GUIDE 


IKorning 

I 

Glass of water—Toilet 

Brrakfaflt 

Fruit, cereals and plenty of milk, eggs, bread and butter. 

No coffee or tea at any meals. 

Eat slowly, walk to school. {Don't run.) 

fcrljnnl 

Going and Coming 

Take ten deep breaths slowly, shoulders straight and head up. 
Don't sneeze near another person. 

Use your handkerchief. Don't spit. 

Momt 

Wash your hands and face; use soap. 

Glass of water before eating. 

Buutrr 

Besides meat and potatoes, or rice, eat plenty of vegetables and only 
plain puddings or fruits. Chew each mouthful thoroughly. 

Afternoon 

Walk slowly after eating. Keep cheerful. 

Play out-of-doors after school. 

hunting 

Wash face and hands. Glass of water. 

g>upp*r 

Plenty of milk and fruits and fish or eggs instead of meat. Fried 
foods are hard to digest. 

Uinimma ©pm 

Top and bottom. 

SLEEP OUT-OF-DOORS WHEN YOU CAN. 

Reduced from Chart. 22-28. Issued by the National Tuberculosis Ass’n., 381 4th Ave., New York 







PHYSIOLOGY AND HYGIENE 


CHAPTER I 

THE BODY IN ACTION 

Did you ever time yourself for a sixty-yard dash? 
Or test how many times you can chin on the bar? Or 
how far you can jump from a standing start? 

These are important questions for boys in the 
schools of many towns and cities which have school 
athletic leagues; for those who can make a certain 
record, providing their school work is satisfactory and 
their physical posture good, are given a badge from 
the Athletic League. 

School athletic records.—This is the record for 
seventh and eighth grade boys that will win a bronze 
badge in some of the leagues: 

6o-yard dash.8 3/5 seconds 

Chinning on the bar.4 times 

Standing broad jump.5 feet 9 inches 

The boy who can make a still better record wins a 
bronze silver badge. For the bronze silver badge, this 
is the record that he must make: 

I 





2 


PHYSIOLOGY AND HYGIENE 


6o-yard dash indoors. 8 seconds 

ioo-yard dash outdoors.14 seconds 

Chinning on the bar. 6 times 

Standing broad jump. 6 feet 6 inches 

Girls also have contests in walking, swimming, 
basketball, relay races and folk-dancing. Girls may 



Start of one-hundred-yard dash 


win honors in these lines the same as the boys in their 
contests. 

Of course it is a high honor to win a badge for phys¬ 
ical strength and skill. Every sensible person desires 
a strong, well-built body, and we also want our bodies 
to show skill in action. 

Success depends on skill. —All the world’s work 
and achievement, as well as its play, depend on 
some form of action. I recently watched a girl writing 











THE BODY IN ACTION 


3 


in a typewriter speed contest. The record showed 
that she was able to make about fifteen separate move¬ 
ments each second with all of the fingers of both hands. 
She received a valuable prize in the contest, and she 
also earns a fine salary. No matter whether we work 
in factory, mine, shop or office, our bodies must be 



Learning muscular control and grace of carriage and movement 


capable of moving quickly, skilfully, and easily, to 
perform whatever tasks we require of them. 

The “master-tissues.” —All the body’s move¬ 
ments of every kind are brought about by the muscles. 
Muscles and nerves have been called the master-tissues. 
This is because of the important work they perform, 
and also because most of the other tissues of the body 
work to support the muscles and nerves. 

Each of us has more than five hundred different 





4 


PHYSIOLOGY AND HYGIENE 


muscles in his body. Some are large and some are 
small, but scientists have studied every one, and given 
each its own separate name. We may be glad that it 
is not important that we should commit all of these 
names to memory. 

The muscles taken together 
make up what we call the flesh 
of the body. When we buy 
beef-steak or any lean meat at 
the market we are buying 
muscles. If you weigh eighty 
pounds you have altogether 
about forty pounds of muscle 
in your body; for your muscles 
make up about one-half of 
your entire ‘weight. 

The part of the tendons. 

—Muscles are attached to 
bones by means of tendons. 

The tendons and muscles of . , . 

the back of the hand A tendon is a very strong, 

whitish, inelastic cord. You 
can easily see the tendons underneath the skin in the 
back of the hand, and feel them as they work. 

The tendons are smaller than the muscles to which 
they are attached. This makes them better able to 
work over joints and at other places, as the hand 
or the foot, where muscles would be too large and 
clumsy. 








THE BODY IN ACTION 


5 


How muscles produce movement. —The muscles 
are elastic; they can contract and expand like a piece 
of rubber. When the muscle at the front of your 
upper arm (called the biceps) contracts it bends the 



The high jump 


elbow joint and draws the hand up toward the shoulder. 
The bones serve as levers for the muscles to act upon. 

Grasp the biceps of your right arm with the other 
hand while you bend your arm as sharply as you can. 
Feel the muscle swell up and become larger around 
as it grows shorter. Have some one measure the girth 
of your arm when it is extended and again when you 
have it tightly bent. The difference in circumference 

2—Jne 21 




6 


PHYSIOLOGY AND HYGIENE 


represents the increased thickness of your biceps when 
it is shortened by contraction. 

Pairs of muscles. —An interesting thing about the 
muscles is that most of them work in pairs. When 
you bend the forearm up toward the shoulder you find 
the biceps in the front of the arm growing large because 
it ^shortened. When you straighten the arm out again, 
if you feel the muscles at the back of the arm you will 
find them growing larger as they pull the arm straight. 
Muscles which flex (or bend) our joints are called 
flexors . Those which straighten the joint out are 
called extensors. 

Muscles which we can control. —Most of our 
muscles are under the control of our wills. That is, 
we can make them act or be still as we please. We can 
move the arm or keep it quiet. We can say to the 
muscles of our legs, “Now make me walk/’ and they 
carry out our orders; we can say to the muscles of 
our arm, “Now strike,” and the blow comes. Muscles 
that we can control in this way are called voluntary 
muscles. 

Other muscles which we can not control.— 

There is another class of muscles, however, that we 
can not control by our wills. Such a muscle is the heart. 
Suppose you try to make your heart stop beating by 
thinking about it. Suppose you say, “I will make my 
heart beat faster just by choosing that it shall.” You 


THE BODY IN ACTION 


7 


soon find that you are unable to control the beating of 
your heart. Your heart goes on in the same fashion no 
matter whether you will that it shall beat faster or 
slower; its muscle is involuntary . 

The muscle which makes up the greater part of the 
stomach and food canal is also involuntary. It will 
not obey our commands. In the same way the muscles 
in our arteries and veins take care of themselves and 
go on doing their work day and night no matter whether 
we are thinking about them or not. 

We may say in general that the muscles that cause 
movements which are always about the same, as the 
beating of the heart, or the action of the stomach, 
are involuntary; they go on acting without any 
attention or direction. On the other hand, muscles 
which cause movements that must be done quite 
differently at different times, such as the movements 
of the arms, legs, or many other parts of the body, 
are voluntary; these muscles move as we direct them 
to move, or remain still when we choose. 

The structure of a voluntary muscle. —You can 

easily understand the structure of a muscle, or how 
it is made, if you will take a piece of lean beef that 
has been boiled until it begins to fall apart. You will 
notice that the muscle separates into small strands, 
and that there seems to be a very thin, almost trans¬ 
parent tissue wrapping around these various little 
strands. 


8 


PHYSIOLOGY AND HYGIENE 


Now if you will take a needle or some other sharp 
pointed instrument, you can still further separate these 
little bundles into smaller fibers. This picking them to 
pieces is called 1 ‘teasing’’ them. If you are careful and 
use a microscope you can keep on teasing the bundles 
out until you have found very small fibers indeed. In 
fact these fibers are so small that it would take five 
hundred of them laid down side by side close together 
to make one inch. 

We may think, therefore, of the voluntary muscle 
as made up of bundles of very small fibers wrapped 
around by thin tissue and then more bundles laid side 
by side with these until the entire muscle is finally 
formed in this way. The heart muscle is made up of 
shorter fibers wrapped up in bundles, while the muscle 
of the arteries, veins, stomach and food canal consists 
of tiny short fibers arranged, not in bundles, but in 
sheets. 

Interesting experiments. — i. Show how muscles 
work in pairs, one bending a joint and the other 
straightening it again. You can illustrate by 
using the muscles of the arms, legs, neck, hips, 
etc. How many pairs of antagonistic muscles 
can you locate? Remember that a muscle which 
bends a joint is called a flexor muscle and one 
that extends a joint, or straightens it out, is 
called an extensor muscle. 

2. Boil a piece of muscle until it begins to separate 



THE BODY IN ACTION 9 

into bundles. Then take two needles and fasten 
them in round pieces of wood somewhat larger 
than matches. Use these instruments to tease 
the separate strands apart to show the smallest 


Chinning the bar placed in a school-room door 

fibers you can discover. Show also the thin 
wrapping tissues that cover the bundles of 
fibers. 

3. Notice the difference in the movements of a 
skilful piano player and one who is just learn- 
















10 PHYSIOLOGY AND HYGIENE 

ing; of a baseball player throwing a ball, and a 
girl throwing it; of a soldier or other person of 
good carriage walking, and a slouchy, “loose- 
jointed” person walking. What other illustra¬ 
tions can you suggest? Explain how one gets 
skill in tne use of his muscles. 

Questions to answer. —What are the usual school 
Athletic League’s requirements for a bronze badge, or 
a bronze silver badge? Why should one develop mus¬ 
cular skill? What are the “master-tissues” of the 
body? Why are they so called? What are the tendons 
for, and where are they found? How do muscles act 
to produce movements? What do we call the muscles 
we control? What do we call the muscles we can not 
control? Of what is a muscle composed? How may 
we go about it to examine the muscle fibers in a piece 
of lean meat? 

Health Problems 

1. Would you rather be in the winner or the loser group in 
the contests pictured in this lesson? What factors will do 
most to determine which group you must join? 

2. Do you know persons who seem to have headache or tooth¬ 
ache or earache or something else the matter with them a 
good deal of the time? How may one escape these ills? 

3. Thousands of dollars are spent by cities and schools upon 
playgrounds for children. Why is this done? What should 
the children do in return? 


CHAPTER II 


THE MUSCLES AT WORK 

When you have chicken for dinner, which piece do 
you prefer, a part of the breast, a leg or a wing? No 
matter which piece you take, you eat muscles. Yet 
the taste is very different, and while the muscle of the 
breast or wing is tender, that of the leg may be 
rather tough. 

You have had beef-steak that was tender and easily 
chewed. Another time you may have had a piece so 
tough that it took all the strength of your jaws and 
all of your patience to masticate it. 

What is it that makes one piece of muscle tender 
and another tough when we come to eat it? 

How muscles grow firm and strong. —In order 
to answer this question, we shall need to refer again 
to the muscle fibers and the way they are wrapped 
together in bundles. Each of these tiny fibers is 
wrapped in its own little sheath, called by the hard 
name sarcolemma (sar co lem' ma), and each of the 
bundles of fibers is also enclosed in its own separate 
wrapper, while several of these bundles are bound up 
ii 


12 


PHYSIOLOGY AND HYGIENE 


into still larger bundles by still coarser wrappers. 
These wrappers which enclose the bundles of fibers 
are not like the sarcolemma,—the sheath of one single 
fiber, but consist of another kind of tissue called con¬ 
nective tissue. It is found in all parts of the body, 
binding all the various parts of organs together and 
strengthening and protecting them. It threads in and 
out among all of the bundles of muscle fibers, binding 
them together and helping to give them their rigidity 
and shape. 

Now there are two things that will make these 
tissues grow hard and tough. One is age. The young 
chicken or turkey is tender because its connective 
tissue has not yet thickened and hardened. The old 
fowl is tough because this tissue has grown dense and 
hard. 

The other thing that will cause muscle to grow hard 
and tough is exercise. The breast or wing of the 
chicken is more tender than the leg because the mus¬ 
cles of the chicken’s breast and wing have but little 
exercise, while those of the legs are constantly used. 
The law therefore is that muscles grow hard and tough 
with age and with use. 

When muscles are not used. —You can easily 
test this difference by feeling of the muscles of a child’s 
arm and then testing the muscles of the arm of a 
blacksmith or some other person who labors with his 
arms. 


THE MUSCLES AT WORK 


13 


Nobody wants 
muscles that are 
flabby and weak 
from lack of ex¬ 
ercise. We want our 
muscles hard, firm 
and tough. And we 
may depend upon it 
that our muscles will 
not possess strength 
and endurance un¬ 
less they are con¬ 
stantly used and 
hardened to their 
work. 

Training the 
muscles of the 
face. —An impor¬ 
tant fact about mus¬ 
cles is the ease with 
which they are 
trained. Suppose 
you now stop and 
think of some person 
whose face usually 
looks solemn, sour, 
and unpleasant. Of course he may smile now and then, 
but the habit of his expression is to be glum. On the 



The way the muscles would look without 
their covering of skin and fat 




14 


PHYSIOLOGY AND HYGIENE 


other hand, think also of some friend whose face is 
cheerful, happy, and bright, and who instead of a 
frown, usually has a smile hovering about his mouth 
and eyes. 

The expression of our faces is caused by the muscles 
which lie just underneath the skin of the face. If these 
muscles have been trained to pull the face into a 
sour expression, if they are accustomed to turn the 
corners of the mouth down, and make a frown between 
the eyes, then they soon keep this form of expression. 
We then have the habit of a sour expression. If, on 
the other hand, the facial muscles have been trained 
to smile, if they have been made to turn the corners 
of the mouth up in place of down, then they easily 
take this position and give us a bright and cheerful 
expression. It is all a matter of habit. The muscles 
easily settle into the form in which they are commonly 
used. 

Muscles that keep the body straight. —This 
same law is seen in the way men carry their shoulders. 
If you look out upon the street as men are going to 
their work, you will see that some have stooped, 
bent shoulders, and that others carry themselves up¬ 
right, with shoulders straight and head up. Some 
stoop because of illness, but the most of these men 
with bent shoulders are the ones who have got into 
the habit of stooping as they work, and their muscles 
have settled into the shape in which they are con- 


THE MUSCLES AT WORK 


15 


stantly used. The men who carry themselves erect 
are the ones who have trained their back and shoulder 
muscles to hold the body erect as they work; and 
their muscles have come to take the form which keeps 
the body straight and in good posture. Have you not 
been surprised at the great difference a few weeks of 



It is easy to see where the winning athletes and strong healthy 
men are to come from 


training in the army have made in some of your 
friends? When they went to camp they slouched 
along as they walked, but now they stand erect, and 
with what a beautiful gait they walk! 

It is important to remember that muscles finally 
come to take the form in which they are most cow.monly 
used. 




16 PHYSIOLOGY AND HYGIENE 

With this law in mind see whether you can answer 
the following questions: 

1. Are any of the pupils in your school room train¬ 
ing their muscles in such a way that they will 
come to have stooped shoulders and hollow 
chests? 

2. Are there any who, because they generally have 
an unpleasant expression of the face, are train¬ 
ing their face muscles into undesirable habits? 

3. Do you know people outside of the school who, 
through wrong postures when at their work, 
have so trained their muscles that their bodies 
are no longer well shaped? Do you know other 
people who have so trained their muscles that 
their bodies are as straight and erect as when 
they were young? 

4. Are you allowing any of your muscles to develop 
undesirable habits? 

Good muscle habits to form. —1. Make the 
muscles of the back and shoulders keep the body 
erect, the shoulders back, and the head up. This 
will not only give you a good carriage, but will 
keep you from becoming stoop-shouldered, hol¬ 
low in the chest and of bad form in general. 

2. Train the muscles used in walking to give you 
a firm, even step, such as shows decision of 
character, rather than to allow a careless, sham¬ 
bling gait, which is always unattractive. 



THE MUSCLES AT WORK 


17 


3. Train the muscles of the face to smile instead of 
to frown. Do not allow them to twitch, grimace, 
or to acquire any other mannerism which is un¬ 
desirable. 

4. Train the muscles of speech to bring out each 
sound clearly and distinctly, not 
mumbling words nor cutting off 
sounds at the ends of words as 
people often do when they say an 9 
for and or goin ’ for going. 

Questions to answer. —What is the 
tissue called which is found wrapped 
around bundles of muscle fibers? What 
is connective tissue and where is it found? 

What is it that makes some lean meat 
tough while other meat is tender? How 
can we make our muscles firm and strong? 

Explain how the muscles of the face act 
to give us different expressions. How Muscles of 
may we train our face muscles so that the leg 
we may have a pleasant look rather than a sour one? 
Why do some persons have stooped shoulders while 
others are straight and erect? What are some muscle 
habits good to form? 



CHAPTER III 


TRAINING THE MUSCLES 

Suppose the boys who read this lesson would like to 
increase the size of their biceps. Suppose the girls 
would like to cure themselves of drooping shoulders 
and hollow chests. What can be done about it? Can 
we change the size and habit of our muscles? Can we 
make them do the work we demand of them? Can we 
change awkward and unskilful muscles into muscles 
that are well controlled? 

We can. It is comforting to know that muscles 
which so easily allow our shoulders and back to take 
wrong shapes and positions can just as easily be 
trained to make them take right ones; and that acts 
and movements which are awkward and bungling can 
be changed into well controlled, skilful ones. 

Developing muscles through use. —Just to show 
how muscles will respond to training: Among my 
friends is a blacksmith, who is large of build and very 
strong. He works with both arms, of course, but he 
works most with his right arm. All day long he keeps 
his right biceps busy as he hammers the iron on his 
anvil. I recently asked him to let me measure the 
18 



TRAINING THE MUSCLES 19 

girth of each of his arms with the biceps drawn up to 
full size. His left arm showed a circumference of six¬ 
teen inches, but his right arm measured nineteen 
inches. 

This difference in size in the blacksmith’s arms had 


Everybody works at the Boy Scouts’ camp 

been caused by years of labor in which the right arm 
had been called upon for more work than the left arm. 
Whatever muscle is exercised, that muscle demands a 
larger supply of blood. The blood brings to the muscle 
additional food material. The muscle uses this food 
supply to increase its size, and so grows larger and 
stronger. 




20 


PHYSIOLOGY AND HYGIENE 


It has been proved many times by actual experiment 
that through proper exercise of the muscles a man of 
average size can increase the girth of his arm around 
the biceps as much as three-quarters of an inch in four 
or five weeks. 

Muscle training and good posture. —The muscles 
of the chest and shoulders can be trained in the same 
way. There is no great trouble in increasing the girth 
of the chest by an inch or two in a few months’ practise. 
It is all a question of proper exercise of the muscles. 
With careful attention given to full, deep breathing, 
and with erect carriage of the chest and shoulders the 
muscles will increase in size and strength. 

In similar fashion we can develop the large muscles 
of the back, which carry the shoulders and hold them 
in position. If we allow the muscles to become slack 
and the shoulders to sag, the muscles grow weak and 
flabby. On the other hand, if we make the muscles 
of the back do their work, if we give them exercise by 
requiring them to hold the shoulders straight and the 
body erect, then these muscles develop in size and 
strength so that they naturally and easily hold the 
body in good posture. 

Muscles quickly respond to training, both in size 
and strength. A muscle soon comes to take the shape 
or form in which it does its work. It develops what¬ 
ever of strength is demanded by the work it has to 
perform. 


TRAINING THE MUSCLES 


21 


Training our muscles to skill. —Muscles must 
also be trained in skill. No one wants to be awkward 
or clumsy in his movements. No one wants to be a 
slow or bungling workman. 

I have a schoolboy friend who has practised until 
he can toss a number of small balls, keeping two in the 
air at one time. He is now working to see whether he 
can not keep three balls in the air. I have another 
friend who is working hard to gain skill on the type¬ 
writer keyboard, so that he may become an expert 
typist and so secure a good position. He also desires 
to enter a typewriting contest soon to be held to see 
whether he can not win a prize. They are both seeking 
muscular skill through careful practise and training 
of their muscles. 

All of us are, of course, seeking to train our muscles 
to skill in many directions. We wish to learn to write 
a good, legible hand with fair speed. We would like 
to play the piano or violin; or we are seeking to perfect 
ourselves in the handling of a tennis racket or a base¬ 
ball bat. If not any of these things, then we are surely 
at work in a score of other directions trying to win 
skill for ourselves in our play or in our work. 

The value of skill. —And this is all as it should be. 
No one likes the bungler. Every one should be ashamed 
of awkwardness which could be overcome by greater 
care and practise. The workman who does not attain 
both skill and speed never secures the higher salary, 

3 


22 


PHYSIOLOGY AND HYGIENE 


and never is certain of his job. The highest pay and 
the highest honors, whether in work or in play, always 
go to the person who has learned to control his muscles, 
and who has made them the most serviceable in carry¬ 
ing out his will. 



Learning skill and developing muscle at the same time 


The boy who is learning to toss the balls has been 
working hard at it for a number of months. Season 
after season boys and girls play at different games, 
perfecting their skill in them. Year after year men 
work at their trades, developing both skill and speed, 
and finally become expert workmen. Through intelli¬ 
gent practise is the only way we can train our muscles 
to high skill. 






TRAINING THE MUSCLES 


23 


This, then, is the law of our muscle training: Skill 
comes only through well directed, faithful and con¬ 
tinued practise. We must not aim simply at improv¬ 
ing a little. We should never be satisfied with the skill 
we have already reached, but must always be aiming 
at something better. We should never say, Oh, that 
is good enough! We must rather say, No piece of 
work or act of skill is good enough until it is the best 
that we can make it! 

Facts worth remembering. —1. Our muscles 
must be trained. Strength and skill do not 
come by chance; we must work for them. Harry 
Houdini, one of the world’s greatest magicians, 
tells how he is able to perform feats no other 
man can do. He says: 

“No one except myself can appreciate how I 
have to work at this job every single day, never 
letting up for a moment. In each town where 
I play I hire an empty stable, or loft, or room, 
and here I put in hours upon hours of study and 
experiment.” Even this great master of his art 
must practise daily to keep up his skill. 

2. Nothing worth while is easy. If we would stand 
well, walk well, write well, play well, or work skil¬ 
fully we must give the time and effort necessary 
to train our muscles to their work. We can not 
stand awkwardly, slouch as we walk, write care¬ 
lessly, play poorly, or work below our best 


24 


PHYSIOLOGY AND HYGIENE 


without having our muscles form bad habits. 
We should strive to work, play, or do whatever 
we do always at our best . 

Problems and experiments. —i. Test the skill 
of your muscles by tossing two balls, keeping 
one in the air all the time. Try sawing a board 
square across by following a scratch line. 

2. Place a sheet of paper on your desk and hold a 
small mirror so that you can see the paper in 
the mirror. Now while watching in the mirror, 
write your name so that it will read right in the 
mirror. Try writing your name in this way a 
dozen or more times. Do you find your skill 
improving with practise? What lesson does this 
teach? 

3. Which ones of your muscles do you think you 
particularly need to train? Think of your 
posture, speech, skill in work, games, etc., before 
deciding. Are you willing to give the care and 
practise necessary to train those muscles which 
require it? 

Questions to answer. —How can we go at it to 
change the shape and size of different muscles? Ex¬ 
plain the lesson taught by the difference in size of the 
blacksmith’s two arms. Why does a muscle which is 
used grow larger and stronger than one which is not 
used? Explain how one may train the muscles of his 
shoulders and chest to hold his body erect. How can 


TRAINING THE MUSCLES 


25 


the muscles be made quick and skilful for work or for 
games? What is the only way to gain skill? Tell the 
story of Houdini and explain the lesson taught by the 
story. Why is mirror writing so much more difficult 
than ordinary writing? 

Health Problems 

1. Make a list of games in which you have fair skill; a list 
of games common to your age and sex which you do not 
know how to play. 

2. Place your open hand, palm down, on the table. Now 
raise and lower your index finger rather rapidly for several 
minutes, keeping the rest of your hand in contact with the 
table. What does this teach you with reference to fatigue? 

3. Notice, as you are among people, what proportion of them 
have stooped shoulders; one shoulder lower than the other; 
heads bent forward; a bad gait in walking. How do they 
come by these peculiarities? 

4. Observe your schoolmates and then describe five habits you 
discover which are bad for health (not mentioning names 
of persons); five that are good for health. How many of 
these ten habits have you? 

5. What are you especially doing to correct any bad health 
habits you may have? What good health habits have you 
in the process of forming? How does one form habits? 
How does he break habits? 


CHAPTER IV 


THE FRAMEWORK OF THE BODY 

Most people have never seen one of their own bones. 
For our bones are all hidden away under the skin and 
the flesh, and one does not have very much to do with 
his bones unless he happens to have an accident and 
break one of them. 

Yet the bones play a very important part in our 
bodies. Yesterday I saw going along the street a boy 
who had iron braces strapped to his legs. They had 
hinges at the knees which bent backward and forward 
as he walked. The poor fellow was having a hard time 
of it, for it seemed that even with these braces his legs 
would hardly bear him up. 

Bones make the body rigid. —The trouble was 
that some disease had kept his bones from hardening 
as they should, and they were therefore unable to 
sustain the weight of his body. Lacking firm, rigid 
bones in them, his legs would bend and probably break 
if he undertook to stand on them without the help of 
the iron braces. So Jamie is a cripple because his 
bones do not make a strong enough framework for 
his body. 


26 


THE FRAMEWORK OF THE BODY 


27 


Just as the house must have 
its framework of timbers in 
order to hold it up and give it 
strength, so the body must 
have its framework of bones. 

Jamie's braces which he 
had strapped to his legs 
were really a steel 
skeleton meant to 
take the place of 
the bones which 
had failed to do 
their part inside. 

We have altogether two hun¬ 
dred and six different bones in 
the body. These are fastened 
together at the different joints 
by very tough, strong, inelastic 
bands called ligaments . This 
framework of bones in the 
body we call the skeleton. 

Structure of a bone.— 

Some time when you were 
having round-steak for dinner 
you may have got the piece 
which contained a round piece 
of bone. This bone was hollow in the center. Sup¬ 
pose you ask for this piece next time and examine the 



The bony framework of the 
body, called the skeleton 





28 


PHYSIOLOGY AND HYGIENE 


substance that fills the center of the bone. It is 
called marrow , and consists largely of fat, oily sub¬ 
stance and of blood-vessels. 

Most of our bones are hollow. All the hollow bones 
have this central tube filled with marrow. 

Each bone has a covering of tough tissue called 
periosteum . If a bone has been broken or has had a 
piece cut out of it new bone tissue will form and the 
broken ends will grow firmly together if the periosteum 
has not been too much injured. 

How bones grow. —I once saw a surgeon perform 
an operation which illustrates how a bone is able to 
repair itself through growth. A man had had the bone 
of his leg broken, and it did not heal properly. Instead 
of growing together the broken edges would slip past 
each other. After giving the man an anesthetic the 
surgeon sawed a strip out of the bone on each side of 
the break. He then fitted one of the pieces he had 
sawed out into the space so that half of its length 
extended on each side of the break. This piece of bone 
served as a key to keep the bones from slipping. The 
surgeon had been careful not to injure the periosteum, 
and the new piece of bone quickly grew fast, and the 
break soon healed. Pieces of bone are sometimes 
transplanted from other parts of the body to repair 
a nose or other part of the face that has had a 
part carried away by a shot in battle or by some 
accident. 


THE FRAMEWORK OF THE BODY 


29 


Bones which have been broken will 
soon knit and be as strong as ever if 
they are properly set. Soon after a bone 
is broken, nature causes the broken place 
to be filled up and surrounded by a fluid 
which hardens into a cartilage-like sub¬ 
stance, and later changes into real bone. 
This cartilage-like substance, called cal¬ 
lus , serves to hold the ends of the bone 
in place while they are healing, and adds 
strength until the injured part has fully 
recovered. It is this callus which causes 
the bone to be larger for a time at the 
place where it has been broken. 

Differences in bones caused by age. 

—The baby’s bones are soft and will 
bend easily. This is why a baby seldom 
breaks his arm or leg when he falls. 

The large bone You have also observed that aged per- 

of the upper leg r 1 1 1 „ 

(called the fe- sons are very caretul when they walk 
Imur) cut length- over slippery places, as if they are 

hollow ^structure afraid of falling. Nature has been wise 
in making the aged cautious, because 
an old person’s bones will break much more easily 
than a child’s. If once broken the bones of an old 
person heal slowly as compared with the bones of a 
younger person. 






30 


PHYSIOLOGY AND HYGIENE 


Bones of the old and the young. —We may com¬ 
pare the bones of the old and the young in this way: 

1. In youth our bones are softer and more easily 
bent. They will keep whatever shape is given 
them at that time. They do not break easily, 
and if broken will heal quickly. 

2. The bones of an older person are more rigid and 
brittle. They will break more easily than in 
youth, and will not heal so quickly when broken. 

Matter of which bones are composed. —It is 

easy to understand the cause of this difference between 
the bones of the young and the old if we remember 
that bones are made up chiefly of two kinds of material: 
(i) animal matter , which gives the bone its toughness 
and elasticity; (2) mineral matter , which gives the 
bone its hardness and stiffness. 

When we are young there is a larger proportion of 
animal matter as compared with mineral matter. As 
we grow older the proportion changes so that there is 
a larger amount of mineral matter. The boy who had 
to wear iron braces on his legs lacked mineral matter 
in his bones to make them rigid. The very aged person 
whose bones break almost as easily as a pipe stem 
lacks animal matter to make them tough and elastic. 

How bones may change their shape. —Perhaps 
you have read how, just to be in style, little Chinese 
girls sometimes have their feet bound up tightly when 
they are very young. Feet kept bound in this fashion 


THE FRAMEWORK OF THE BODY 


31 


can not grow. They remain so tiny that girls with 
bound feet can hardly walk. For when the baby’s 
bones are soft they are easily made to take whatever 
shape or size is forced upon them. 

We do not bind the feet of our babies. We do, 
however, sometimes change the natural shape of our 
bodies in such a way as to bring on a deformity. For 
example, boys and girls who have the habit of sitting 
in a slouchy manner may when they are older never 
be able to walk erect. 

Keeping the body straight. —We can better 
understand how such deformities come about if we 
consider a few facts about the structure of the back¬ 
bone. The spinal column or back-bone is made up of 
twenty-four little bones, resting one on top of the other 
with small pads of cartilage in between. Cartilage is 
a tough and springy substance somewhat like felt or 
rubber. It is what we call gristle when we find it in 
meat. 

These pieces of cartilage act as elastic cushions to 
save the body from jolting and jarring as we walk. 
The pads of cartilage naturally press together some¬ 
what from the weight of the body. The effect of this 
is that we are somewhat shorter at night than in the 
morning. While we sleep these little pads take their 
natural shape again, so that we are full height every 
morning. 

It is easy to see that if we keep our backs bent 
forward and our shoulders stooped a great deal of the 


32 


PHYSIOLOGY AND HYGIENE 



The spinal column. 
Note the separate 
vertebrae with the 
thin layer of carti¬ 
lage between 


time the little cartilage cushions will be 
pinched at the front edges or on one side 
and made thinner at those points. If 
the constant pressure continues from 
day to day because of bad postures, the 
cartilage cushions finally come to keep 
the unnatural wedge shape, which gives 
us the stooped shoulders and bent back¬ 
bone. As we grow older the cartilage, 
like the bones, hardens and can not 
easily be made to take its former shape. 

Correcting wrong shape. —The 

important thing to remember is that 
both bones and cartilage are much 
more easily shaped by the pressure or 
strain upon them when we are young 
than when we are older. It is therefore 
very important that boys and girls 
should keep the best possible postures 
of the body and not allow their bodies 
to become bent or deformed. 

As long as we are young we can do 
much to correct any wrong shape 
which the body may have taken. If 
our shoulders have become stooped or 
our spine crooked through bad pos¬ 
tures or any other cause, we can do 
much to correct them. We shall 



THE FRAMEWORK OF THE BODY 


33 


need constantly to 
keep watch that 
we maintain such 
postures as will re¬ 
lieve the pressure 
which has caused 
the deformity. 



Things that 
help. —The “set- 
ing-up” exercises 
of the soldier, the 
gymnastic drills of 
our school gymna¬ 
siums, and the cor¬ 
rect, easy carriage 
of boys and girls 
who know how to 
control their bodies 
all tend to give us 
a good body 
framework. 

On the other 

hand all slouch i- Little danger of this Girl Scout developing a 
7 . curved spine or round shoulders. Note her 

neSS OI Carriage, all straight carriage 

wrong postures in 

work,—in short, all carelessness of posture when we 
stand or sit or walk is sure to give us a body frame¬ 
work that is out of true proportion. 





34 


PHYSIOLOGY AND HYGIENE 


Interesting things to do.—i. Get a piece of 
fresh bone at the meat-market and study the 
edge where it has been sawed off. Point out 
the canal of the bone. Show the marrow. See 
whether you can find blood-vessels in it. Can 
you see where the blood-vessels pass through 
holes in the bone to the inner tube? Point out 
the thin, tough, wrapping coat called the peri¬ 
osteum. Tell what makes the bone pinkish in 
color. 

2. If your school can supply you with a bottle of 
muriatic acid, place in it the leg of a chicken, 
and leave for several days. Then take the bone 
out and wash the acid from it and show that the 
bone is no longer rigid and stiff, but that it is 
so plastic that it can even be tied in a knot. 
This is because the acid removes the mineral 
matter and leaves but the animal matter in the 
bone. (Remember that muriatic acid is a 
strong poison.) 

3. Take another leg of the chicken or some other 
piece of bone. Place it in an iron shovel or a 
metal pan and burn it for half an hour or more 
in a hot fire. Then show that the bone is brittle 
and can even be crumbled between the fingers. 
This is because the fire has burned out the 
animal matter and left but the mineral matter. 


THE FRAMEWORK OF THE BODY 


35 


Questions to answer. —What are all of the bones 
of the body taken together called? Explain two great 
uses of the bones. How many bones are there in the 
body? How are bones tied together at the joints? 
How are our muscles fastened to bones? What is the 
fatty substance found in the hollow of a bone called? 
Why are the bones of an old person more easily broken 
than the bones of a child? Why are the bones of a 
child more easily bent than the bones of an older per¬ 
son? Explain how bones may be made to change their 
shape. Explain how a stooping position as we work 
may give us a crooked spine or bent shoulders. How 
may a crooked spine or bent shoulders be corrected? 
Why does a bone placed in acid become soft so that 
you can bend it? Why does a bone which has been 
burned in the fire become brittle? 

Health Problems 

1. Although children seem to have many more falls than 
older persons, they less often break bones in such accidents. 
Explain why this is. 

2. Mention a number of deformities that are caused by some¬ 
thing being wrong with the bones. 

3. Just what has happened to the bones when a person has 
had his neck or his back “broken”? Why is the arm more 
easily dislocated at the shoulder than the leg at the hip 
joint? 

4. Give an account of any accident of which you may know 
which resulted in a broken bone. How long did it take 
the bone to heal? 


CHAPTER V 


JOINTS AND BODY MOVEMENTS 

I once visited a hospital where I saw a man ill of 
some disease that made it impossible for him to turn 
his head, bend his knees or his elbows, or use almost 
any other joint of his body. I was told that the dis¬ 
ease stiffened the joints so that he had practically no 
joints at all. I then understood more clearly than I 
ever had before just what joints are for. Without 
joints we could have no movement of any part of the 
body. 

Kinds of joints. —About the best way to under¬ 
stand joints is to examine a number of our own. Sup¬ 
pose you begin by bending your finger at the first or 
second joint. You soon discover that you can get 
motion in only two directions—backward and forward 
like a hinge. Such joints are called hinge joints. 

Now if you will try moving your wrist, you find that 
you can move it in several directions. The eight small 
bones in the wrist joint glide over one another and allow 
a wider range of movement than the hinge joint. This 
kind of joint is called a gliding joint. 

Next try moving your head in as many directions as 

36 


JOINTS AND BODY MOVEMENTS 


37 


possible. You observe at once that you can nod your 
head backward and forward and also turn it from side 
to side. This is arranged for by a special kind of joint 
which is called a rotary joint. 

Now try swinging your arm from the shoulder in 
every direction possible. You will 
find that it has a very wide range 
of motion. In fact you can move 
it in more directions than any of the 
other joints that you have exam¬ 
ined. The shoulder joint is of the 
kind called ball and socket . The 
hip also moves on a ball and socket 
joint. 

We have other joints that are 
not meant to allow movement. 

Joints of this kind are found unit¬ 
ing the bones of the skull. 

The wearing surface of joints. 

—In all movable joints the surface 
of each bone is covered with a cap 
of cartilage . This has a hard, tough, smooth surface, 
which allows the bones to move easily and with little 
friction. The membrane of the joints gives out a thick, 
oily fluid which serves the same purpose for the joint 
as the oil that we put on the machine. 

The movable joints are, as we saw in the last chapter, 
fastened together by tough, inelastic bands called 



The knee joint, with a 
ligament showing at 
each side. Not all the 
ligaments are shown 


38 


PHYSIOLOGY AND HYGIENE 


ligaments . When these ligaments are over-strained or 
torn loose, we have a sprain. 


The work of ligaments. —Sometimes a sudden 
strain or wrench upon a bone is sufficient to throw the 
joint out of place. This accident is commonly known 
as a dislocation . The shoulder joint which has a rather 
shallow socket is 
one of the most 
easily dislocated 
joints of the body. 

When a bone is 
thrown out of joint 
or dislocated, it 
should be imme¬ 
diately put back 
in position. It is 
usually necessary 
to have the doctor 
do this, although 
one who under¬ 
stands joints may m the socket 

sometimes accomplish it successfully 
out the aid of a doctor. 

Strength with free movement. —The 
strongest of the movable joints of the body 
is the hip joint. This has a very deep 
socket, and is therefore not easily thrown out of joint. 
Since the hip joint is required to support the weight 




JOINTS AND BODY MOVEMENTS 


39 


of almost the entire body every time we step, it is 
easy to see why this joint must be strong and firm. 

Nature has been doubly careful that the hip joint 
shall not be thrown out of joint. This is accomplished 
by tying the head of the thigh bone into the socket 
by stout ligaments which makes it impossible for dis¬ 
location to occur without a strain severe enough to 
break the bone itself. 

When joints grow stiff. —When a joint is bruised 
and can not be used for a time, as when a bone is broken 
or a severe sprain has occurred, the joint may become 
stiff. Joints require exercise to keep them in good 
working order and cause the oily fluid to flow. The 
joints of many of the aged grow stiff and their ligaments 
harden because of slight chronic inflammation. The 
effects of these changes are easily seen in the walk and 
carriage of some who are old. 

A painful inflammation of the joints, popularly 
called rheumatism, but more correctly arthritis 5 often 
occurs. Arthritis frequently causes the joints to 
swell and become stiff. It was formerly thought that 
this ailment was caused by living or working where it 
is damp. Now we know, however, that it is caused by 
germs. The germs get into our blood from some source 
of infection, such as diseased tonsils or decayed teeth. 
The cure for arthritis is, of course, first of all to re¬ 
move the source of infection from which the germs 
come and then to limber up the joints by proper exercise. 


40 


PHYSIOLOGY AND HYGIENE 


Interesting things to do. — i. Locate on your 
own body as many of the different kinds of 
joints as you can, writing down a list of them 
under the heads: hinge , ball and socket , gliding , 
rotary , immovable. 

2. Bring from the meat-market a fresh joint from 
the leg of a beef or a pig from which most of the 
meat has been removed. Show the ligaments 
that hold the bones in place. Test them for 
strength. If you can get a hip joint show the 
ball and socket and the loose ligament that ties 
the ball to the center of the socket. 

3. On a fresh joint show how the wearing surface 
is covered with cartilage. Note how smooth the 
surface is. Show the oily fluid which lubricates 
the joint. 

4. See whether you can find several of the vertebra 
bones of some animal. The butcher may be 
able to help you. Possibly the doctor could 
lend some of the bones from a human skeleton. 
Show how the vertebrae fit together. Show the 
canal for the spinal cord. 

Questions to answer. —What are joints? What are 
the different kinds of joints found in the body? Tell 
where at least one of each kind of joint is found. Explain 
how bones are fastened together at the joints. What is a 
sprain? What is a dislocation? How are joints sometimes 
made stiff? WVhat is the remedy for stiffened joints? 


CHAPTER VI 


THE FOOT AND ITS CARE 

I have just been out watching some boys who are 
training for a track meet soon to be held at the school. 
Their trainer was explaining to them how to get a 
quick start when the signal is given. He was also show¬ 
ing them how to use their feet in order to get a springy, 
fast stride. He was urging upon the boys that one can 
never be a good runner if he does not have the best 
of feet. 

The foot is made up of a wonderful combination of 
twenty-six bones. These bones are fastened together 
by large bands of ligaments, and are connected by 
strong tendons to the muscles of the leg. 

The work of the foot. —The foot has very hard 
work to do. It must hold up the entire weight of the 
body at every step. Not only must the foot be strong, 
but it must be elastic and springy enough to give the 
body an easy, graceful carriage. 

A good many people have poor feet. Their feet may 
be so weak as to give trouble in standing when at work. 
Or the feet may lack the strength and elasticity to give 
easy movement in walking or running. 

41 


42 


PHYSIOLOGY AND HYGIENE 


Flat-foot, or broken arches. —One of the worst 
foot troubles is that called flat-foot , or broken arch. 
In flat-foot the muscles of the lower leg and ankle are 
too weak to support the weight of the body on the 
foot. The ankle bends inward and the inner edge of 
the foot helps bear the weight of the body. The 
springiness that comes from the arch of the instep is 
lost, and a heavy thumping gait is the result. 



Impression left by a normal, well-shaped foot 


The best test for flat-foot is to take the impression 
of the bare foot on a piece of paper when the sole of 
the foot is damp or when coated with powdered char¬ 
coal. The strong, well-shaped foot will give the marks 
of the toes, the ball of the foot, the outer edge of the 
foot and the heel, leaving a sharp circle underneath 
the arch. The flat foot will leave an impression on the 
inner edge as well as the outer. 

Tests for flat-foot. —Another evidence of flat-foot 
is the way we wear our shoe heels. If they wear off 
on the inside edges rather than wearing evenly over 




THE FOOT AND ITS CARE 


43 


the entire heel, it indicates that our ankles are turning 
in, and that we are threatened with flat-foot. In flat- 
foot the toes also have a tendency to point outward 
as we walk. 

A flat foot is always weaker than a normal foot 
and therefore quickly tires. A flat-footed person often 
finds that walking produces pains in the feet or in the 
legs or the back. 



Impression left by a flat foot 


The doctors tell us that more than one school boy 
and girl out of ten have flat-foot. Thousands of men 
have had to be rejected from our army because of 
flat-foot making it impossible for them to stand march¬ 
ing and the work of the soldier. 

Wrong styles in shoes. —The easiest way to dis¬ 
cover the cause of flat-foot is to go to a shoe store and 
look over the styles of shoes. Many of them have soles 
much narrower than the foot, and so do not give a 
broad enough basis to stand or walk easily. The 




44 


PHYSIOLOGY AND HYGIENE 


balance of the body must therefore be held by the 
muscles of the leg. These soon tire, grow weak, and 
allow the ankle to turn in. When this has gone on 
for a little time the muscles and tendons have become 
accustomed to the wrong position, and the first thing 
we know we are flat-footed. The high heels worn by 
girls not only weaken their feet but prevent them from 
having an easy, natural carriage. 



The position which high heels The way the foot should rest 
make the foot take in the shoe 


On the whole I think we treat our feet very badly. 
We are shocked when we learn that the Chinese have 
been accustomed to binding the feet of their babies to 
keep them so small that they can go into tiny little 
shoes. The Chinese are stopping this barbarous cus¬ 
tom, however, while we still wear shoes which are often 
too tight, that do not fit the shape of the foot, that 
have narrow soles and high heels. 



THE FOOT AND ITS CARE 


45 


The right kind of shoes. —Every boy and girl 
should hunt for shoes that meet the following con¬ 
ditions: 

1. The shoe should fit comfortably, but not be so 
loose as to allow the foot to slide around in it. 

2. The shoe should be the shape of the foot in its 
natural form as we stand with our weight upon 
it. 

3. The soles should be broad enough to give a good 
basis upon which to balance the body’s weight 
as we stand or walk. 

4. The heels should be broad and low. 

Curing weak feet. —If one finds that he has flat- 
foot he can do much to cure it. The growing boy and 
girl should not wear arch supports since these will 
prevent strengthening the muscles and so curing the 
condition. The first thing to do of course is to secure 
shoes that will measure up to the four rules which we 
have just given. The muscles of the lower leg and 
foot can be strengthened by rubbing and exercising 
them each evening as we retire. 

We can strengthen the muscles also by specially 
planned exercises. A good method is to stand squarely 
on the bare feet and lift the body as high as possible on 
the balls of the feet. Do this as many times as you can 
without tiring or overstraining the muscles. Carry 
the exercises through each night and morning, increas- 


PHYSIOLOGY AND HYGIENE 


46 

ing the number of times the body is raised as the 
muscles grow stronger. Also practise morning and 
evening walking on the outer edges of the bare feet. 

Corns. —A great many people are troubled with 
corns on their feet. A corn is a hardened growth in 
the skin which presses down on the sensitive nerves 
and causes much pain. Corns are caused by some 
unnatural pressure or rubbing. 

The most common cause of corns is narrow shoes that 
crowd and pinch the toes, or shoes that are too loose 
and so rub some part of the foot. 

By far the best treatment for eorns is never to 
grow them. If a corn is once formed there is little use 
to try to cure it unless we remove the cause. We 
must therefore remove the pressure or the rubbing. 
If we do the corn will drop off. Get the shoes that 
will fit, cut a hole out over the corn, or put an insole 
in a shoe that is too large. If you pare a corn, be sure 
that the toe and the knife are clean for there is danger 
of infection; however, paring will not stop the growth 
of a corn. 

Interesting problems and experiments. — 

1. Let each member of the class stand with the 
bare foot on a sheet of paper. Have some one 
trace around your foot with a pencil, thus taking 
an impression of your foot. Bring this tracing 
to school and determine how many of the class 


THE FOOT AND ITS CARE 47 

wear shoes that (1) have soles the right size, 
(2) have soles the right shape for the foot. 

2. Shoes should have reasonably thick soles, so 
that the foot may have a solid support for the 
weight of the body, and so that the dampness 
may not easily pass through. Notice the shoes 
worn to school and judge them on these points. 
How about your own shoes? 

3. Girls often wear shoes with heels that are both 
too high and too narrow. This gives the foot 
a cramped, unnatural position, and injures the 
gait in walking. Are any of the shoes worn to 
school to be criticized on this point? 

Questions to answer. —Why is it especially neces¬ 
sary to have good feet? How many different bones in 
the foot? Explain what is meant by flat-foot. What 
causes flat-foot? How can you tell whether a person 
has flat-foot? How may a flat foot or broken arch be 
cured? Why is it important that one should have 
shoes of the right size and shape? Describe the kind 
of shoe that one should wear. What are corns? How 
are corns caused? How are corns to be cured? 

Health Problems 

1. Make a study of twenty or thirty pairs of old shoes, noting 
whether heels and soles are evenly worn. Do you find evi¬ 
dences of flat foot? Of bow legs? 

2. Describe the kind of shoes you think boys and girls should 


wear. 


CHAPTER VII 


HOW THE BODY IS CONTROLLED 

It would be impossible for any one to count all of the 
different movements made by the five hundred or more 
muscles of the body in play or in work. In some kinds 
of work or play almost every muscle of the body is 
brought into action at the same time. Some of the 
muscles act with almost incredible rapidity, as we can 
readily understand if we watch the fingers of a pianist 
flit over the keyboard. 

Muscles are controlled by nerves. —No one of 

these muscles acts of its own accord. No muscle 
moves until it is directed to move. Only when muscles 
are controlled and governed by nerves do they con¬ 
tract, and thereby produce movements. 

One of my friends was among the first of the Amer¬ 
ican soldiers to go to France after America entered 
the European war. Nobody knows exactly how it 
happened, but one day when he was in the trenches 
a shell exploded near by and a piece struck him. He 
lost consciousness and when he regained his senses he 
was in a hospital surrounded by doctors and nurses. 
He said he felt no great pain, but he was unable to 
move any part of his body from the hips down. 

48 


HOW THE BODY IS CONTROLLED 


49 


His muscles were all right and the skin had not even 
been broken. There was a bruise, however, over his 
back-bone. This hurt explained the difficulty. The 
doctors told him that two or three of the small bones 



Good nerves no less than good muscles will determine the winner 


in the spine had been injured in such a way as to 
pinch the spinal cord just where the nerves come out 
which govern the lower part of the body. 

An operation was performed which removed the 
pressure of these bones upon the nerves and our soldier 
soon found that he was able to move his legs again. 








50 


PHYSIOLOGY AND HYGIENE 


He slowly recovered and was as well as ever in a few 
months. 

Strength of muscle depends upon the nerve 
currents which flow over the nerves to the muscles 
just as electricity flows over a wire. —No matter 
how good the muscles, nor how strong they are, their 
actual strength depends more on the nervous system 
which controls them than on the muscles themselves. 

There is a little instrument called by the big name 
dynamometer , which is to measure how strong one is 
in his hand, how much he can grip with his fingers. 
Now the amount that you can grip does not depend 
altogether on the strength of your muscles and ten¬ 
dons. It depends even more on the health and vigor 
of the nervous system which governs your arm and 
hand. In the same way if you test how heavy a 
weight you can lift, the amount you lift is not deter¬ 
mined chiefly by the strength of your muscles, but by 
the nervous mechanism which controls those muscles 
to make them act. 

The nervous system determines quickness and 
endurance. —It is just the same when you run a 
race. The quickness and length of your stride does 
not depend alone on your muscles, but also on the 
nerve currents that run to them. 

So also with one’s endurance. You may have run 
in a race until you could hardly drag one foot after 


HOW THE BODY IS CONTROLLED 


51 


another, then found that when you were nearing the 
goal you were capable of a sudden burst of speed. 
This was because a new supply of nerve energy was 
sent down to your muscles by the thought that you 
were almost at the end of the race. The endurance 
that one can show really depends more on his nerve 
power than on his muscle power. 

As a matter of fact the nerves play the most impor¬ 
tant part in determining our muscular skill. My small 
friend who is learning to keep three balls in the air 
at one time is really training his nerves more than he 
is training his muscles. 

Skill depends on nerves. —Expert divers tell us 
that there is a certain moment in the dive in which one 
must poise the body at just such an angle in order to 
strike the water right. If the nerves do not govern 
the muscles right, the correct movement is not made 
and the dive is not a success. 

No matter how well any act of skill is learned, the 
nerve currents which govern it must continue to be 
correct if mistakes are not to be made. No railway 
company or other concern will to-day put a man in 
a position of responsibility if he is known to drink. 
This is because alcohol always injures the steadiness 
of the nerves and interferes with acts of skill. The 
engineer who drinks is likely to pull the throttle a 
little too far or at just the wrong instant and so cause 
an accident. The motorman who drinks is likely to 


52 


PHYSIOLOGY AND HYGIENE 


be bewildered at some moment of excitement on the 
street and fail to make the right movement with his 
switch or brake. 



Out for a basket. But he needs steady nerves as well as 
trained muscles 

Nervous embarrassment interferes with skill.— 

I have a young friend who plays the piano well when 
he has only his teacher for an audience. But he says 
that whenever anybody is watching him or listening 
to him his fingers all seem to go wrong. This is because 
he has not yet learned to play before company, and 
his embarrassment disturbs the nerve currents which 



HOW THE BODY IS CONTROLLED 53 

govern his hands and arms. He will never be really 
skilful until he gets over his embarrassment in play¬ 
ing before people. For no matter what the cause, 
anything that disturbs the natural flow of nervous 
energy into our muscles will interfere with their action 
and thus make skill impossible. 

Important facts about nerves and muscles.— 
The following are important points to remember con¬ 
cerning the control of the body by nerves: 

1. No muscle contracts or expands except under 
the direct control of a nerve. 

2. The strength, skill, and endurance of our muscles 
are all dependent on the supply of nervous 
energy coming in to them over the nerves. 

3. Anything that interferes with nervous action, 
such as the poison of alcohol, fatigue, or even 
mental embarrassment, will cause an irregular 
flow of nervous energy into the muscles, and 
hence disturb whatever skill we may have 
acquired. 

4. We may say, then, that our muscles are no 
stronger or better than our nervous system which 
controls them. 

Problems and experiments. —1. In the case of 
an accident or in a time of great danger men 
have been known to exert much more strength 
and show more endurance than they could do 
in ordinary times. Explain why this is possible. 


54 


PHYSIOLOGY AND HYGIENE 


2. Tobacco is known to be especially injurious to 
the nerve centers and therefore to interfere with 
the nerve control of muscles. With this fact in 
mind explain why athletic coaches and trainers 
will not allow their players to use tobacco dur¬ 
ing the athletic season. 

3. When you are engaged in some long, hard task 
that tires you, notice whether you feel capable 
of increased speed and skill as you near the end. 
Explain this. 

Questions to answer. —By what are muscles di¬ 
rected and controlled? Upon what does the strength 
and quickness of our muscles depend? Why is it nec¬ 
essary to have “strong nerves” if one would have 
good endurance? Explain how acts of skill, like 
diving, depend upon trained nerves. Why can one 
not do so well when he is frightened or embarrassed? 
Why can one sometimes exert more strength or show 
more speed in times of great danger than in ordinary 
times? How does tobacco or alcohol affect nerve 
strength and control? 

Health Problems 

1. The basket ball team did good work when they were prac¬ 
tising for the championship game, but when the game 
itself came they showed the effects of “nerves.” How can 
fear or nervousness in such trials of skill be overcome? 

2. If you had to run a mile, would you start out at your best 
clip, or start more slowly and increase your speed gradually? 


CHAPTER VIII 


BRAIN AND NERVES 

The nervous system which controls the action of 
the body and does all our thinking is so wonderful 
that it will be worth while to learn something of 
its structure. 

The nervous system consists (i) of the brain, (2) of 
the spinal cord, and (3) of the nerves which connect 
the different parts of the body with either the brain 
or the cord. 

The brain. —The brain is shut away in the tightly 
closed box which we call the skull. The bones of the 
skull are so strong that the brain is quite thoroughly 
protected from ordinary injuries by blows or accidents. 
At the age of fourteen years your brain weighs be¬ 
tween two and a half and three pounds. It increases 
but little in size after this time, but goes on developing 
for many years. 

The main part of the brain which fills all the upper 
part of your skull is called the cerebrum . It is divided 
into two parts or hemispheres connected by a little 
bridge, very much as the two halves of an English 
walnut are joined together. The surface of the cere- 
55 


56 


PHYSIOLOGY AND HYGIENE 


brum is covered over with deep ridges, or folds, which 
makes its appearance still more like that of a walnut. 
The spinal cord extends from the brain downward 
through a canal in the bones of the spinal column to a 
point about the waist line. The cord is silvery white 
and is about the 
size of your little 
finger. 

Nerves. — The 

nerves act as mes¬ 
sengers between 
the different parts 
of the body and the 
brain or cord. If 
you look carefully 
at a piece of lean 
beef before it has 
been cooked you 
will be able to find 
in it tiny silvery 
white threads. 

These are nerves. The b ra i n as it appears in its bony chamber 

The nerves which carry the messages of sight, sound, 
taste, smell, touch, or other sensations into the brain 
or cord are called sensory nerves. Those which carry 
orders for movements from the brain or cord out to 
the muscles are called motor nerves. 

The brain has twelve nerves for each side of the 





BRAIN AND NERVES 


57 

body. Some of these are sensory, some are motor, 
some are both combined. These connect the eyes, 
ears, nose, face, and some of the internal organs with 
different parts of the brain. 

The spinal cord has thirty-one sensory nerves and 
thirty-one motor nerves for each side of the body. 

Each nerve, as it extends from the cord or the brain, 
begins to branch like a tree and keeps on subdividing 
until it ends in thousands of little fibers. It is by this 
branching and subdividing that the forty-three nerves 
are able to reach all parts of the body. So completely 
do the nerve endings cover the skin that it is almost 
impossible to find a spot where a sensory or motor 
nerve does not reach. 

Division of work. —Just as in a factory each group 
of men are assigned their own particular work to do, 
so in the brain different parts or areas do their own 
special work. For example, your nerves of sight run 
to the very back part of your brain. If you will 
put the tips of your fingers at the back of your head 
about as high as the top of the ear, you will then have 
them resting directly over the sight center. If this 
particular spot is injured, you cap not see, no matter 
how perfect your eye or how good your nerve of 
sight. Your hearing center lies at the side of the 
brain just above the level of the ear. 

The muscles of your legs, arms, upper part of the 
body, face, and eyes, are controlled by a narrow 


PHYSIOLOGY AND HYGIENE 


58 

section of the brain extending from in front of the ear 
upward and slightly backward. The movements of 

your speech organs are in 
part governed by a small 
area about the size of a 
silver quarter of a dollar 
lying slightly in front of 
the left ear and near the 
level of the top of the ear. 

It is thought that the 
front part of the brain is 
chiefly concerned with our 
thinking. 

Whenever a sound is to 
be heard the nerves of the 
inner ear carry the message 
in to the right place in the 
brain and we hear! When 
an object is to be seen, a 
picture, or image, of it is 
formed on the back part of 
the eye; the nerve of sight 
carries the message in to 
the proper spot in the brain 
and we say, I see a tree,* 
a cloud, a person! 

When we taste, the substance must be dissolved in 
the fluids of the mouth. There it comes in contact 



The white lines show some of the 
main branches of the nerves reach¬ 
ing to all parts of the body. There 
are thousands of smaller branches 
which are not shown 


BRAIN AND NERVES 


59 

with the little “taste buds,” which are located in small 
red dots or points scattered over the tongue. Here again 
a message is started in to the brain, this time over the 
nerve of taste, and you say salt, sweet, sour, or bitter! 

How nerves act. —So it is with smell or touch, or 
heat or cold, or any other sense. Some proper stim¬ 
ulus excites the little end organ of the sensory nerve; 
the nerve faithfully carries the message in to the 
right part of the brain, and the mind gets the infor¬ 
mation necessary to know the fact it requires. 

When movements are to be performed the plan is 
the same, except that the message now runs out over 
a motor nerve from the brain or cord to the muscle. 

For example, the mind gives the order, Pick up the 
pencil and write. Immediately a nerve message starts 
from the right area of the brain, runs down over motor 
nerve fibers to the cord, and so on out to the arm and 
hand, and the act is performed. 

Nerve habits. —Acts or movements that have been 
performed many times come to “do themselves”; that 
is, the act becomes a habit, as we have already learned. 
But even though the act may be performed without 
ever thinking about it or intending it, the fact still 
remains that the nerve message ordering the move¬ 
ment to be made must come from brain or cord; it 
must run out over a motor nerve pathway to the 
proper muscle, and the muscle must then contract and 
expand so as to produce the required movement. 


6o 


PHYSIOLOGY AND HYGIENE 


It is clear then that we need good eyes, ears and 
other organs of sense so that we may secure the nec¬ 
essary information from the world of sight, sound, 
taste, smell, etc., around us. We need good brains to 
receive these messages from the outside world, and to 
think and plan. We need good motor nerves and strong 
muscles to carry the mind’s thoughts and decisions 
out into acts and deeds. 

If we are wise, therefore, we will 
do nothing to harm any of our sense 
organs, such as the eyes or ears. Al¬ 
cohol, which injures many organs some¬ 
what, hurts the brain and nerves 
worst of all. Even very small 
amounts of this poison can be 
proven to lessen the efficiency 
of the nervous system, while 
long use produces serious 
injury. We should not know¬ 
ingly injure the nerves that 
bring the messages and carry orders out to the mus¬ 
cles. We should not take into the body alcohol, tobacco 
or any other poison that will affect the brain. For 
to injure either brain or nerves means to decrease our 
power to think and the power to carry our thoughts 
out into deeds. 

Interesting things to do. — i. After studying the 
drawing of the brain on page 56 place the tip of 



A section of the 
spinal cord show¬ 
ing sensory and mo¬ 
tor nerve roots 




BRAIN AND NERVES 


61 


your finger over the spot on your brain where 
hearing is located; sight. 

2. In the same way point out the part of your 
brain which controls the movements of your 
arms, legs, face, etc. 

3. The movements of the speech organs are con¬ 
trolled by a small area on one side of the brain 
only. If you are right-handed the speech center 
is on the left side of your brain; if left-handed, 
the speech center is on the right side of the brain. 
Now point out your own speech center. 

4. Look in a mirror or at some other person’s 
tongue and find the red spots where the ‘Taste 
buds” are located. On which part of the tongue 
are they scattered thickest? 

Questions to answer. —What are the different 
parts of the nervous system? Where is the brain found? 
What is the upper and larger part of your brain called? 
Describe the cerebrum. What two classes of nerves 
are there? What is the work of the sensory nerves? 
What is the work of the motor nerves? How many 
nerves are there running to and from the brain? How 
many nerves attach to the spinal cord? Explain how 
the spinal cord is protected. What part of your brain 
is responsible for seeing? What part is responsible for 
hearing? What parts of the brain control our muscles? 
What part of the brain is concerned chiefly with our 
thinking? 


CHAPTER IX 


THE NERVE CELLS AND FIBERS 

One of the smallest living things is a tiny animal 
called the amoeba. The amoeba is so small that it 
can not be seen without a microscope. When you first 
look at it under the microscope you will be disappointed 
if you expect to see an animal with head and body 
and legs or wings like those you are accustomed to see. 

For the amoeba is an animal of only one cell. It 
looks like the smallest particle of the white of an egg. 
It can change its shape and in that way it moves about 
slowly. The single cell of which the amoeba consists 
is made up of what is called protoplasm. This proto¬ 
plasm is alive! 

Cells and tissues. —The interesting thing about all 
this is that every tissue of our bodies—muscles, blood, 
bones, brain, etc.—is made up of living cells of proto¬ 
plasm. These cells differ in size and shape, but all are 
too small to be seen by the eye alone. 

One particular kind of cells is found only in our 
brain and nervous system. These are called nerve 
cells. The work of these cells is so important that it 
will be worth while to learn more about them. 

62 


THE NERVE CELLS AND FIBERS 


63 

Nerve cells. —About a block from where I live 
stands a large building made of brick. I know there 
must be many thousands of brick in its walls, yet 
from where I sit I can not see any one particular brick. 
They all blend together in one great 
mass, which I see only as a building. 

This illustrates the structure of our 
brain and nervous system. When we 
look at the brain, for example, it seems 
to consist of a single mass of rather soft 
material. But if we will tease a small 
portion of the brain apart, as we did the 
muscle, and then look at it through the 
microscope, we will see that the brain is 
made up of millions upon millions of 
separate nerve cells. These tiny cells 
form the brain just like the bricks make 
the wall. 

How the nerve cells work. —The 

nerve cells of brain and spinal cord differ 

. . . , , , ... A nerve cell 

in size and shape, but they are all alike 
in one particular: Each consists of a tiny body of 
living protoplasm and of thread-like fibers which grow 
out from the cell’s body. We may liken the cell body 
to an electric battery and the fibers to the wires. 
Each cell lives its own life and does its own work. 
In general, we may say that the cell body part of 
the nerve cell supplies the energy or force by which 




PHYSIOLOGY AND HYGIENE 


64 

the brain does its work, and the fibers carry this energy 
where it is needed. 

No one can explain exactly how it takes place, but 
we know that all of our thinking, all of our feeling, 
and all of our acting are made possible by the work of 
the nerve cells. 

We are able to learn acts of skill and to form habits 
that make us more efficient in our work because the 
nerve cells can become accustomed to doing these 
things. If we form bad habits or do our work bun- 
glingly it means that our nerve cells have not yet devel¬ 
oped proper control over the muscles. 

When we master the multiplication table, commit 
to memory a poem, or learn how to spell a new word, 
we have trained our nerve cells to work together on 
these things. For learning of any sort depends finally 
on the training of our nervous system. 

When, on the other hand, we forget a fact we have 
known, when we misspell a word, or when we are 
unable to recite a poem we have committed, it means 
that some of our nerve cells have, from one cause or 
another, failed in their duty. 

Things that injure the nervous system.— 

When we see how important these cells are it is easy 
to understand that anything which will injure them or 
interfere with their action will harm our thinking and 
lower the skill of our acts or movements. 

The surest way to injure the cells of the nervous 


THE NERVE CELLS AND FIBERS 65 

system is by different kinds of poisons, for, as we have 
seen, a nerve cell is a living thing and may be poisoned 
just as an animal may be poisoned. Tobacco is a harm¬ 
ful poison and tends to injure the nerve cells. 

Under the influence of tobacco the heart becomes 
weaker, irregular and uncertain in its action. It is 
this effect which gives the smoker what is called 
“tobacco heart.” The tobacco heart beats now too 
fast and now too slow. 

But a still worse poison for the nerves is alcohol. 
Alcohol injures practically every tissue of the body, 
but seems to have a special grudge against the brain 
and nerves. Careful experiments made by doctors and 
other scientists have shown that the nerve cells of ani¬ 
mals which have been given alcohol are shrunken in 
size and made feeble in their work. It is this effect 
that makes the hands of the drinker uncertain, his mind 
befuddled and all of his powers below their best. 

Tired nerves. —Still another poison to which all of 
us are subject is that which comes from fatigue. Ex¬ 
periments have been made upon pigeons, sparrows, 
and other birds which fly long distances at great speed. 
It has been found that their nerve cells shrink very 
noticeably when the birds are greatly fatigued. These 
cells recover their full strength and activity only after 
a period of rest. 

This fact explains not only why we have the feeling 
of fatigue when we have exercised or studied for a long 


66 


PHYSIOLOGY AND HYGIENE 


time, but also why we can not do as good work when 
we are very tired. The brain by which we do our 
thinking and which governs our movements is for the 
time being poisoned by fatigue, and can recover its 
tone and strength only through rest. 



A good way to rest after a hard year's work in school 

Important facts to remember. —i. The work 
of your brain and nerves is done by the millions 
of cells of which they are composed. 

2. Each cell is complete in itself, and joins with 
others of its kind to do the work of our think¬ 
ing and acting. 

3. The nervous system can be trained so that it 
gives us good habits or bad habits. 



THE NERVE CELLS AND FIBERS 


6 7 


4* The nervous system needs good care. It re¬ 
quires the nourishment that comes from suitable 
food. It should not be injured by poisons from 
alcohol, tobacco or any other source. 

Questions to answer. —What is an amoeba? Why 
is it called a one-celled animal? What is a cell? Ex¬ 
plain how the brain is made up of many cells. Explain 
how cells are grouped together to make nerves. Why 
are nerve cells so important? What effect do tobacco 
and alcohol have on the nervous system? How do 
nerve cells act when they become tired? 

Health Problems 

1. Why do people often become cross and irritable when they 
are very tired? What ought they to do when they feel 
this way? 

2. Suppose you have been using your brain all day studying 
at school, would you better rest by outdoor play or by 
sitting in the house reading a story? Why? 

3. Why do drunken persons find it impossible to speak their 
words right, saying “thish” for “this,” and so on? 

4. Our habits are really formed in the brain and nervous 
system. Our brains are more plastic and easily molded in 
youth than when we are older. What, then, would you 
conclude as to the best time to form desirable habits? 

5. Make a list of the five worst habits you can discover among 
the pupils of your school. 


CHAPTER X 


THE NERVOUS SYSTEM AT WORK 

Some persons have better brains than others. How 
good a brain one has depends partly on heredity 
on what kind of brain was given him at birth; but it 
also depends a great deal on the training and develop¬ 
ment we give our brains. 

The baby can not learn hard lessons nor think things 
out for himself; his nervous system is not developed 
enough to make study and hard thinking possible. 
The baby's muscles are not so skilful and well con¬ 
trolled as yours, for the same reasons—the cells which 
direct his muscles are not yet able to do their full 
work. 

The nervous system trained by use. —Our brains, 
like our muscles, develop daily by being used. The 
nerve cells and fibers that carry messages of sight or of 
sound must be given work to do; we must notice and 
observe. 

The nerves that contract our muscles must be 
given practise in many kinds of exercise and movement; 
we must work, play, train ourselves to skill in move¬ 
ment; we must develop our motor nerve cells. 

• 68 


THE NERVOUS SYSTEM AT WORK 69 

The cells by which we do our thinking must also 
have their training. We must learn right habits of 
study and reading. We must train our memory and 
attention. We must learn to plan, reason and think 
things out for ourselves. 

Youth the best time for training. —It is easiei 
to train our brains when we are young than after we 
become older. The hunter finds that if his setter dog 
is not trained to point game at an early age, it is 
impossible to give the right training later. It is “hard 
to teach an old dog new tricks,” for the older the 
brain becomes the more difficult it is for it to learn new 
lessons. 

This is one reason why boys and girls should attend 
school regularly and improve their time while there. 
Many things are learned more easily in early youth 
than later. When we are young is the best time, there¬ 
fore, to learn to study, and to form habits of effort, 
persistence and thoroughness which every person 
needs for his success. 

The effect of an injured nervous system. —The 

development of our brains may be affected by acci¬ 
dent or disease. Not long since I visited in a home 
where I saw a woman who was about thirty years of 
age. She was of usual size and strength, but she had 
a childish, undeveloped look on her face, and she was 

busy playing with dolls! 

6 


70 


PHYSIOLOGY AND HYGIENE 


Of course, it seemed very strange to see a grown 
person acting like a little girl. Her family explained to 
me the cause of her condition. When this woman was 
a little girl of about eight years the children went out 
skating one winter day and Mary fell on the ice, strik¬ 
ing her head a terrible blow. 

' She was carried into the house insensible, and fever L 
developed. After a time she seemed to recover, but 
something had happened to her brain. The brain 
never developed beyond the point it had reached on 
the day of her fall. Her brain remained like the brain 
of a child of eight years. Although Mary had been 
very bright, she was incapable after the injury of 
learning from her books, or of understanding things 
about her. When her brain stopped growing her mind 
ceased its development, and although now almost 
middle-aged Mary still is a child mentally and will 
always remain so. So closely is the mind linked with 
the brain. 

The mind injured by harm to the brain.— 

Injury to the brain may cause insanity. I once knew 
a man who was working as a bricklayer on a great 
building that was going up. A heavy iron beam 
which was being hoisted by chains swung out of posi¬ 
tion and, when he was not looking, struck him on the 
head, knocking him to the ground senseless. As soon 
as he regained his senses, he sprang to his feet and 
most violently attacked his fellow workmen who .were 


THE NERVOUS SYSTEM AT WORK 71 

trying to help him. The ambulance was called, and 
he was taken to a hospital still raving. 

The surgeons who examined him said that a bit of 
bone had been crushed in by the blow and pressed on 
the brain at a certain point. It was this that caused 
his raving insanity. The surgeons immediately per¬ 
formed an operation, prying the piece of bone away 
from the brain so that the pressure no longer continued. 
Soon after the pressure on the brain was relieved the 
man regained his natural state of mind and was no 
longer violent nor insane. Here again we see the close 
relation between the brain and the mind. 

Effect of alcohol on the brain. —It is well known 
that a man who is drunk loses his ordinary common 
sense and becomes silly and foolish. His thoughts no 
longer work as they should, for he has so affected the 
nerve cells that they are for a while unable to carry 
out their usual work. The drunken man's brain is 
disarranged like some delicate machine that has been 
thrown out of adjustment. 

Good moods and disposition. —Every one knows 
how good it feels just to be alive on a beautiful day 
when we are well and bubbling over with cheerfulness. 
It is likely that most of us also know what it is to have 
the “blues,” to get into the “dumps,” or to feel cross, 
crabbed and sour when things go wrong, or when 
some slight ailment affects us. This condition of our 


72 PHYSIOLOGY AND HYGIENE 


feelings, whether of brightness, happiness or the blues, 
we call our moods . 



It is very important that we should be in good 
moods because our moods grow 
into disposition and character. 

A certain girl of my acquaint¬ 
ance grew up in a very unfor¬ 
tunate way. In the first 
place this child’s health was 
not good, and her nervous 
system was not in normal 
condition. Added to this 
she was often made un¬ 
happy and cross by being teased 
and scolded. The result was 
that her moods were generally 
bad. Her face wore a scowl and 
her mind was filled with bitter¬ 
ness. Because she continued 
in this state of mind from day 
to day her disposition grew at 
last to be sour, ugly, and for¬ 
bidding, until to-day she is not a very pleasant person 
and does not have many friends. 


Good health and the habit 
of smiling will go far toward 
insuring a good disposition 
and a pleasing manner 


Another child, a boy whom I know, grew up in just 
the opposite way. Every one in his home was good- 
natured and happy; cheerfulness was the rule of the 
day; teasing was banished by common consent. Un- 


THE NERVOUS SYSTEM AT WORK 


73 


kind words and faultfinding were always discouraged, 
and everybody seemed to try his best to be pleasant 
and good-natured. It is needless to say that this boy 
has grown into a youth of most lovable disposition 
and character. 

How character grows. —Tell me the kind of moods 
you live in from day to day and I will tell you what 
your disposition and character soon will become. The 
way you use your brain to-day will determine the kind 
of brain that you will have for your mind to work 
through to-morrow. You can not fill your mind with 
worry, fretting, crossness, ill-nature, jealousy, and 
bitterness without training your brain to a disposition 
that will make you unhappy and cause you to be 
unpleasant to your friends and associates. 

On the other hand, suppose you keep your body in 
health, your mind full of good cheer and happiness, 
and your thoughts occupied with pleasant things. 
Then your brain will so become accustomed to habits 
of good cheer and happiness that your disposition and 
character will be pleasant and you will have many 
friends. 

Interesting things to think about. — i. How 

many different kinds of birds do you know? 
How many kinds of trees? Of wild flowers? 
How many different birds can you recognize by 
their notes? Have you the habit of noticing 
things about you—is your observation good? 


74 PHYSIOLOGY AND HYGIENE 

2. What games or other acts of skill do you excel 
in? Is your penmanship good, and are your 
written lessons neat, thus showing good control 
by your motor nerves? 

3. Do you often get sour or cross? Do you have 
the '‘blues”? Do you ever pout and remain in 
a bad temper? Or are you generally happy and 
cheerful? What difference will this make in 
your disposition? 

4. Judging from your answers to number three, 
what kind of a disposition do you think you are 
developing, good or bad? 

Questions to answer. —What two things determine 
whether we have good brains or not? How are our 
brains to be trained? What is the best time for train¬ 
ing the brain? What may hinder the development of 
our brain? What story can you tell to show that the 
mind is closely connected with the brain? Why is a 
drunken man’s mind foolish and silly? What is meant 
by our moods? Explain how moods may grow into 
disposition . Tell also how character is formed. 

Health Problems 

1. What do you think are the qualities of disposition that 
make people like us and desire us for friends? Do you 
think we can cultivate desirable dispositions and cure our¬ 
selves of bad traits? 

2. Did you ever know a person who would be pleasant enough 
to strangers or friends and then be cross and faultfinding 
at home? Where do you think good nature should begin? 


CHAPTER XI 


GETTING RID OF FATIGUE 

Every one knows the feeling of fatigue—what it is 
to be tired. Every one knows, too, that when we are 
very tired we can not do our best either in work or in 
play. 

We can better understand about fatigue if we know, 
to begin with, that long-continued activity, either of 
muscle cells or nerve cells, manufactures a poison. If 
this poison is not produced too rapidly, that is, if we 
do not get too tired, it is washed out from the tissues 
as fast as it is made, the blood carries it away, and we 
do not seriously feel its effects. 

The poison of fatigue. —If, however, we become 
too greatly fatigued, if fatigue continues for too long 
a time, or if the circulation of the blood is not good, 
then the load of poison becomes more than the blood 
can take care of. It is this fatigue substance which 
gives us the feeling of weariness when we are tired. 
It is also the effects of this poison which cause our 
muscles and nerves to act less efficiently when we are 
very tired than when we are rested and in good phys¬ 
ical condition. 


75 


76 


PHYSIOLOGY AND HYGIENE 


We are not to understand that it harms one to 
become tired. A reasonable amount of fatigue does 
one no injury. In fact it is necessary for health and 
development that we exercise enough to feel some 
degree of fatigue. For in order to use our muscles, 
heart and lungs sufficiently to keep them in good 
health and strength we must exert ourselves enough 
that some fatigue is felt. 

Only severe fatigue injures. —It is only when 
fatigue is too severe, or when it is too long continued 
that it becomes harmful. The over-fatigued cell is 
soon an injured cell. To illustrate, I have a friend, a 
brilliant lawyer, who has broken down from overwork. 
His law practise was heavy and he did not take suffi¬ 
cient exercise and recreation. After a little time he 
felt extreme weariness and did not rest well when he 
tried to sleep. He would awaken in the morning 
feeling almost as tired as when he went to bed. This 
continued for a time, and then he became actually ill, 
and the doctor now tells him that he will have to be 
away from his work for at least half a year. 

Exercise a cure for brain fatigue. —Every school 
boy and girl has noticed that we often come from the 
school room in the evening feeling very tired, and per¬ 
haps out of sorts. A good game of ball or a romp 
through the woods will then rest us wonderfully and 
make us feel as good as new. 


GETTING RID OF FATIGUE 


77 


This is because the exercise in the open air has 
started our blood to flowing faster, and the fatigue 
substances have been washed out of our tissues. It 
is easy to see, therefore, why one who is fatigued from 
brain work needs to exercise his muscles in the open 



Digging clams while the tide is out. The next thing will 
be a “clam bake” 


air. This sets the heart to beating and the blood to 
surging through every part of the body, and the fatigue 
poisons are swept away, so that we again feel rested 
and fresh. 

Massage for muscle fatigue. —The other day I 
went to a field meet, where a number of runners were 
competing in races. I noticed that the trainers and 
coaches were rubbing or massaging the muscles of the 





78 


PHYSIOLOGY AND HYGIENE 


runners between races. This was to rest them and 
help prepare them for the next race. In fact, mas¬ 
saging will bring an almost immediate feeling of relief 
and restfulness to any one who is fatigued. 

It is clear why massaging the muscles will relieve the 
feeling of fatigue. For the kneading, pulling, twisting 
and rubbing of the muscles in massage increases the 
flow of the blood through them. The faster the blood 
flows through the muscles the more quickly will the 
fatigue substances be washed out of them, and the 
sense of fatigue leaves us. 

Rest and sleep remove fatigue. —One of the 

surest and best ways to remove fatigue poisons from 
our bodies is through rest and sleep. Who has not 
gone to bed after a busy day feeling almost too tired 
to undress properly, and then awakened in the morn¬ 
ing feeling as bright and as fresh as if he had never 
thought of being weary! We should be able thus to 
rest quickly and completely. If we are in good health 
and our blood circulation is strong, nature, by remov¬ 
ing the fatigue poisons from our muscles and nerves 
while we sleep, makes us ready during the night to 
begin a new day as fresh as ever. 

Fatigue from worry. —Worry is one of the worst 
causes of fatigue. Some people have the habit of 
worry. They worry over their work instead of getting 
at it to complete it. They worry for fear the rain will 


GETTING RID OF FATIGUE 


79 


spoil the game or the trip. They worry over their 
examinations, though by daily mastering their lessons 
they are sure to pass them. In short, after one has 
once formed the habit of worry, he finds it easy to 
worry over anything or nothing. And all this worry 
is sure in the end to injure his nervous system and 
interfere with his work. 

Important facts to remember.—i. Fatigue is 
accompanied by poisons left in our tissues. 
These poisons must be carried away by the blood 
in order that we may be rested and well ready 
again for work or play. 

2. If the fatigue is not too severe or continued for 
too long a time, the poisons are easily removed 
and no harm is done. The poisons of some slight 
diseases of which the person is scarcely conscious 
produce this same feeling of fatigue. A constant 
feeling of weariness and lack of ambition may 
show that fatigue poisons are being left in our 
tissues or that we have some slight illness. Loss 
of health is sure to follow if these poisons accu¬ 
mulate. 

3. Safe rules to follow.—Stop short of very ex¬ 
treme fatigue, either physical or mental. Ban¬ 
ish worry, ill temper, fretting and spite; they 
not only injure the disposition, but greatly in¬ 
crease fatigue poisons. Exercise wisely, get 
plenty of sleep, breathe deeply of fresh pure air. 


8o 


PHYSIOLOGY AND HYGIENE 


Problems and experiments. —i. After going to 
bed very tired do you awaken in the morning 
fully rested, or do you still feel weary? Do you 
ever feel rested if you have not slept well? Do 
you have fresh air blowing into your room, and 
is the temperature cool enough for good sleeping? 

2. Try bringing on muscular fatigue in two differ¬ 
ent ways, as follows, and watch the feeling of 
fatigue as it grows: (i) Take a standing posi¬ 
tion and hold a book in your hand with your 
arm extended for two or three minutes. < (2) Take 
a comfortable sitting position with your feet 
resting squarely on the floor. Now with the heel 
remaining on the floor tap with the toe of one 
foot as fast as you can for several minutes. 
Does the tapping finally become slower and 
rather irregular? Why? 

3. The person who works all day with his muscles 
can rest best by sitting or lying still. The person 
who works with brain can rest best by some 
game or other activity that uses his muscles. 
Explain the difference in the way of resting. 

'Tell how boys and girls should rest after a day 
in the school room. 

Questions to answer. —What is the result of long- 
continued fatigue? How is fatigue poison removed 
from the tissues? Does it harm one to get moderately 
tired? Give the case of the lawyer who broke down 


GETTING RID OF FATIGUE 


8l 


from overwork. Explain why a good romp or a good 
game will rest us after a day in the school room. How 
does massage help remove fatigue from the muscles? 
Tell one good reason why people should learn not to 
worry. Give four good rules to follow with reference 
to fatigue. 

Health Problems 

1. Do you ever get too tired to be hungry? Or too tired to go 
to sleep? Is it well to carry fatigue to this point? 

2. Do you feel rested and refreshed after a night’s sleep, 
ready for a new day, or do you sometimes awaken still 
tired and dreading to go at your work? What causes 
might lead to the latter condition? 

3. Explain how one may often rest by change of exercise or 
occupation. 

4. How many hours should one of your age sleep each night? 
How many hours do you sleep? 

5. Give rules to be followed in order to get the rest and recu¬ 
peration necessary from our sleep. 

6. Have you ever noticed that you dream troublesome dreams 
when you have eaten indigestible food before going to bed? 
Do you ever dream at night about things that worry or 
excite you during the day? 

7. What rules can you give which will favor your going to 
sleep promptly upon retiring? 

8. What rules can you give which will favor your waking up 
quickly at the proper time, feeling refreshed and ready for 
another day? 


CHAPTER XII 


THE BLOOD AND ITS WORK 

Blood necessary to the life of the body. —Blood 

is so necessary to the welfare of the body that the loss 
of even a moderate amount causes great weakness. 
The boy or girl who reads this book has about three 
or four quarts of blood in his or her body. If one-half 
of this blood should suddenly be drawn off, death 
would follow. 

The danger from loss of blood is shown in a news¬ 
paper item telling of an accident which occurred in 
Chicago. Two small children were left alone while 
their mother went shopping. They found a sharp 
paring knife and were playing with it. In some way 
the younger child received a deep cut across the wrist. 
This opened the large artery there, and the blood poured 
out in a stream. When the mother returned, the little 
one was dead from the loss of blood. The cut itself 
would not have been serious, but the blood supply of 
the body had drained out. Without blood the body 
can not live. 

Blood and strength. —Good blood is necessary to 
health and strength. In a hospital near where I sit 
82 


THE BLOOD AND ITS WORK 


83 


writing, a woman lay ill and almost dying from some 
disease which had affected her blood and made it un¬ 
able to nourish her body. Her weakened blood was 
so useless that it was much as if a vein or artery had 
been opened and her blood allowed to run out. The 
physician said that if she could have a quart or two of 
good, fresh, strong blood put into her veins her life 
might be saved and she would have a better chance to 
recover. 

This woman had two sons, both strong, healthy 
fellows. The sons came to the hospital and the sur¬ 
geon removed a pint of blood from each and injected 
it into the vein of their mother. This brought about 
improvement in her condition and she recovered. 

It can not be too strongly impressed upon us that 
health, vigor, growth, strength—even life itself—de¬ 
pend on a good supply of healthy blood driven through 
the body by a strong heart. 

What the blood is. —We will understand the na¬ 
ture of the blood better if we study the various parts 
of which it is made up. The blood consists of three 
different parts or substances: (1) the liquid part, 
which is called plasma; (2) the red corpuscles; and 
(3) the white corpuscles . 

The plasma. —Although the blood looks red, the 
liquid part, or plasma, is almost colorless and nearly 
transparent. The plasma is nearly nine-tenths water. 


84 


PHYSIOLOGY AND HYGIENE 


Yet this watery liquid carries dissolved in it the food 
material for the nourishment and growth of all the 
different tissues of the body. 

The bread, milk, meat and eggs you have for your 
dinner are picked up by the blood as soon as they are 
digested. They become a part of the plasma. The 
plasma then carries this liquid food to the various 
tissues of the body, where each cell 
picks out the particular food mater¬ 
ials needed for its growth and repair. 
The food you eat to-day, thus distri¬ 
buted by the plasma of the blood, 
becomes the muscles, bones, nerves 
or fat of your body to-morrow. 

Besides carrying the food supply 
to the tissues, the plasma does still 
other important work of transpor¬ 
tation. It has dissolved in it 
many kinds of waste material which it gathers up 
and helps remove. It also carries floating in it the 
red and the white corpuscles. 

The red corpuscles. —It is the red corpuscles which 
give the blood its color. The word corpuscle means 
small body . The red corpuscles are so very small 
that you can not see one of them without a powerful 
microscope. They are so small that many millions 
of them are found in one drop of blood. 

Red corpuscles are disk shaped, each side being 



The red corpuscles as 
they show under the 
microscope. The larger 
circular body is a white 
corpuscle 


THE BLOOD AND ITS WORK 


85 


concave, or slightly hollowed inward. Under the 
microscope they look something like small coins, except 
for being concave instead of flat on the sides. The 
red corpuscles are manufactured in the marrow that 
fills the hollow bones, and pass from there into the 
blood. 

Work of the red corpuscles. —The great business 
of the red corpuscles is to carry 
oxygen from the lungs to the 
different tissues of the body. 



The red corpuscles have the 
power to absorb oxygen, much 


The circular disks are red cor- 


. x iic L.11 cuicn uiaKa are rea cor- 

aS a Sponge takes up water. puscles very highly magnified. 
As the blood comes in contact The irregular bodies are white 


corpuscles 


with the air cells of the lungs 


each red corpuscle absorbs its tiny load of oxygen 
and rushes away in the current of the blood carrying 
its precious burden to some tissue which is given the 
oxygen it requires. 

Oxygen has the effect of making the corpuscles a 
brighter red. Thus oxygen-laden blood coming through 
the arteries from the lungs is of a bright scarlet color. 
When the corpuscle has lost its oxygen it takes on a 
dark, purplish hue. Hence the blood that is on its 
way through the veins back to the heart has a darker 
color than that in the arteries. 

The white corpuscles. —The white corpuscles are 
a little larger than the red corpuscles. They also are 


7 


86 


PHYSIOLOGY AND HYGIENE 


much too small to be seen except with the aid of a micro¬ 
scope. They are irregular in shape. In fact,' they have 
the power to change their shape, and so are found in a 
great variety of forms. It is by changing their shape 
that they move about; that is, they project a part of 
themselves in the direction in which they wish to go 
and then flow or move in that direction. 

There are not nearly so many of the white corpuscles 
as of the red. The proportion is not always the same, 
but in general we may say that there are about seven 
hundred red corpuscles for every white one. The work 
of the white corpuscles is so important that we shall 
take it up for further study in another lesson. Suffice 
it to say now that their great work is to fight the dis¬ 
ease germs that get into the body. 

How nature stops bleeding. —You have noticed 
that the bleeding from a scratch or cut soon stops of 
its own accord. This is because when blood is exposed 
to the air it thickens, or coagulates . This is nature's 
method of stopping the bleeding of a wound and of 
forming a healing covering over a cut. The coating 
of blood that hardens over the edges of a wound is a 
better healing salve than any medicine that has ever 
been invented. 

Interesting problems and experiments. — i. The 

next time your father kills a chicken for dinner 
you might ask him to save some of the blood 


THE BLOOD AND ITS WORK 87 

in a dish. After the blood has stood for several 
hours note that it is no longer red as it was at 
first, but that there is a darkish mass or clot 
floating in an almost transparent liquid. The 
clot consists of practically all the corpuscles 
entangled in a network of fibers, called fibrin , 
which formed in the plasma; the clean yellow 
liquid in which the dark mass floats is the serum.. 
The serum is the plasma after the fibrin has all 
separated out. 

2. When you have had the nose bleed, you may 
have noticed that the blood comes from the 
nostril at times in small clots. Explain how the 
dots are formed. 

3. A boy whom I know has great difficulty to stop 
the bleeding from the smallest wound, a slight 
cut sometimes continuing to bleed for hours. 
The physicians say his blood lacks fibrin , the 
substance which causes clotting. Think how 
troublesome and dangerous all cuts and wounds 
would be if nature had failed to provide for the 
clotting and hardening of blood when outside 
the veins and arteries. 

4. Children sometimes hold their breath when 
angry until their faces become purple, or almost 
black. Recall the effect of oxygen on the red 
corpuscles, and then explain the dark color. 


88 


PHYSIOLOGY AND HYGIENE 


Persons who have been drowned or suffocated 
turn dark in the same way. Is the cause the 
same? 

Questions to answer. —How necessary is blood to 
the body? About how much blood has a boy or girl 
of your age? Tell the story of the child whose wrist 
was cut while its mother was away. Tell the story of 
the woman who had fresh blood put into her veins from 
the veins of her sons. What three parts does the 
blood consist of? Describe the plasma. Describe the 
red corpuscles. What is the work of the red corpuscles? 
Describe the white corpuscles. Tell how nature stops 
bleeding from a wound. 

Health Problems 

1. Many patent medicines are advertised as “blood purifiers.’' 
Is there any such thing as a blood purifier? (The blood is 
pure unless some diseased condition of the body is putting 
a poison into it. In this case the disease should be cured, 
then the blood will be pure.) 

2. When the doctor wants to make sure whether his patient 
has typhoid fever he draws a drop of blood from him and 
has it examined. How can it be told from the blood whether 
the patient has typhoid? 

3. Tie a string tight around your finger and leave it for fifteen 
minutes. What is the appearance of your finger? What 
causes this appearance? 


CHAPTER XIII 


THE CIRCULATION OF THE BLOOD 

We have seen in the preceding lesson how necessary 
the blood is to the life of the body. But in order to be 
of use the blood must be in constant circulation. Let 
the heart cease for only a few moments to drive the 
blood on its endless round through arteries and veins, 
and the person dies as surely as if his blood had been 
drained away. 

Every one is to-day familiar with the fact that the 
blood circulates over the body. We have even meas¬ 
ured the speed at which it moves, and know that the 
whole blood supply is pumped the entire round of the 
body in less than one minute. It seems strange to us 
that even scientific men did not know these facts 
in ancient times. 

Discovery of the circulation of the blood.— 

True, even the ancients knew that the blood is con¬ 
tained in tubes, and that an animal or a man dies 
when the heart stops beating. They also knew that 
there are different kinds of vessels or tubes for the 
blood. One kind they called veins, and the other arteries . 
They made a strange mistake at this point, however. 

89 


9 o 


PHYSIOLOGY AND HYGIENE 


The veins, they said, carry the blood of the body, and 
the arteries carry a ‘Vital fluid” similar to air. They 
were led into this mistake, no doubt, through studying 
the blood-vessels of a dead body. The blood of a person 
who has died settles in the veins, leaving the arteries 
empty. Hence the ancients thought that the arteries, 
even during life, must contain nothing but air, or 
some “vital fluid.” 

We owe the discovery of the circulation of the blood 
to the English scientist, Harvey, who lived about three 
hundred years ago. He performed a series of brilliant 
experiments in which he proved beyond all question 
that the blood flows in a ceaseless current throughout 
all parts of the body. He also proved that without 
this constant flow of blood one can not live beyond a 
few minutes. 

The blood affords a transportation system.— 

We may think of the blood and the machinery for its 
circulation as a great transportation system. The 
blood-vessels are like canals, and the heart is an engine 
which keeps the current always moving. 

Whatever substance or material needs to be moved 
from one part of the body to another is thrown into 
the blood channel, by which it is carried along to its 
destination. The cells and tissues must have food; 
so the blood current receives the digested food and 
sweeps it along to the places where it is required. 
Every part of the body must have its supply of oxygen; 


THE CIRCULATION OF THE BLOOD 


91 



so the blood goes to the lungs, takes on a load of oxygen, 
and delivers it to the tissues that need it. Waste mat¬ 
ter must be removed; so the blood washes up the waste 
from among the cells of the body and bears it away. 

The heart. —For cen¬ 
turies people have known 
that the heart is an im¬ 
portant organ, but just 
what the heart does was 
not known until modern 
science showed us what 
its work is. The heart 
has been called “the seat 
of life,” and was thought 
at one time to be the 
source of our affections 
and feelings. Even yet 
we speak of a person as 
being “good hearted.’ ’ 

But now we know that 
the heart has only one 
function, that is to keep the blood moving. 

The heart is a very strong pump, or syringe. It 
consists of a hollow muscle, divided into four cham¬ 
bers, two on the right side and two on the left. The 
two upper chambers are called auricle s, and the two 
lower chambers ventricles. The auricle on each side 
opens downward into the ventricle under it. 


The heart with its larger blood-vessels. 
The parts marked A are the auricles. 


92 


PHYSIOLOGY AND HYGIENE 



The chambers of the heart.— Some day when 
your mother is serving boiled heart for dinner it will 
be worth your while to notice the structure of the 
heart before. it is cooked. The auricles at the top 
are rather small and their 
walls thin. The greater part 
of the mass is made up of 
the walls of the ventricles, 
which are much thicker. You 
will note that the muscle of 
the left ventricle is much 
thicker than that of the 
right. 

The explanation of the 
difference in thickness of the 
muscle walls is very simple. 
Nature gives each part the 
strength required of it by 
its work. The auricles serve 
as cups to receive the blood 
as the veins bring it back 
to the heart and merely empty it into the ven¬ 
tricles. The ventricles, when they have received the 
blood from the auricles through small gateways or 
valves between the two, must force it to all parts of 
the body. It is clear then that the auricles will need 
less strength than the ventricles. The left ventricle is 
much thicker and stronger than the right ventricle^ 


The chambers of the heart and 
their blood-vessels 





THE CIRCULATION OF THE BLOOD 


93 


this is because the left ventricle drives the blood 
throughout the body, while the right ventricle sends it 
only through the lungs. 

The 1 ‘beats” of the heart are the contracting and 
expanding of its muscular walls. This goes on at 
different rates, as we have already learned, but usually 
from seventy to eighty times a minute. Exercise, 
excitement, and stimulants such as alcohol and certain 
other drugs, cause the heart to beat faster. The heart 
also beats more rapidly when we have fever. During 
sleep or when we are at rest the action of the heart is 
slower. 

The arteries. —The tubes leading away from the 
heart are the arteries. Opening from the left ventricle 
is the aorta , the largest artery of the body. This 
artery branches and subdivides like the trunk of a 
tree, until it has given rise to thousands of smaller 
arteries leading to different parts of the body. 

The left side of the heart receives the blood as it 
comes from the lungs, where it has been purified. The 
blood driven out through the aorta and to the arteries 
connecting with it is therefore fresh and pure, its 
bright red corpuscles laden with oxygen for the tissues. 

Place your finger at a certain spot near the outside 
of the front of your wrist and you can feel your 1 ‘pulse” 
beat. What you feel is really the throb, or expansion 
and contraction, of the radial artery which happens to 
come near the surface at this point. The arteries have 


94 PHYSIOLOGY AND HYGIENE 

elastic walls, and they expand with every throb of the 
heart, because the heart-beat sends a wave down the 
arteries just as a stone thrown into a smooth pond 
sends a wave over the water. 

Old age and certain diseases cause the walls of the 

arteries to harden, and 
by hardening to become 
smaller so that they are 
less able to carry blood 
to the various organs. 
The condition of the ar¬ 
teries is so important that 
the doctors sometimes 
say “a man is as old as 
his arteries.” 

The veins. —The work 
of the veins is to carry 
back to the heart the 
The chief arteries and veins of the neck blood that the arteries 

have carried away from it. The veins, too, have elastic 
walls, but the waves caused by the heart-beat have 
spent themselves before they reach the veins, so they 
do not throb as the arteries do. 

If you will let your arm hang down until the blood 
has had time to settle somewhat in it, and then stroke 
along a vein pushing the blood toward the hand, you 
will notice small knots appearing along the vein. 
Each of these knots shows the location of a small valve, 



THE CIRCULATION OF THE BLOOD 


95 


or pocket, inside the vein. The purpose of these valves 
is to keep the blood from flowing backward from the 
heart. 


The valves of the veins are small flaps, or 
sacks, growing out of the side wall of the 
vein. When the blood is moving toward the 
heart, the flaps lie flat against the in- 
i-Vdli/£ S s j^ e 0 £ thg vein, if the blood starts 
to flow backward, the flap is pushed out so 
that it closes the vein and so checks the flow. 

Since the blood carried by the veins has 
made its tour of the body it is impure. It 
has lost its oxygen, and taken on a load of 
carbon dioxide and other waste material. It 
has lost its bright red color and is of a darker 
hue. When the veins have returned the 
blood to the right side of the heart it will be 
driven by the right ventricle to the lungs to 
be purified again. 

The capillaries. —We have now seen how 
A section the arteries carry the blood away from the 
showing heart and how the veins bring it back again, 
its valves But how does the blood get from the arteries 
over into the veins? And of what use to the 
body is^the blood in the arteries and veins? For their 
walls are quite thick and no food or oxygen can pos¬ 
sibly leave them. These are questions that puzzled 
the scientists for many years. Finally, with the help 









96 PHYSIOLOGY AND HYGIENE 

of their microscope they discovered that the arteries, % 
which as we have learned keep on branching into 
smaller and smaller tubes, continue this branching 
until the little vessels are so small that they can not 
be seen with the eye alone. 

The microscopic vessels in which the arteries end 
are called capillaries , a word which means hairlike. 
The capillaries then unite to form a vein, much as 
small rivulets and streams join to form a larger river. 

The blood gets from the arteries 
to the veins, therefore, by passing 
through a network of very small 
vessels, the capillaries, which are 
found in all parts of the body. 

The capillaries differ from the 
smallest arteries from which they 
arise and also from the smallest 
veins into which they empty, since 
their walls are so thin that the 
plasma of the blood can pass 
through them, carrying food to the 
tissue. It is while slowly moving 
through the capillaries that the blood does its work. 
Here it gives up its food substances to the tissues, and 
gathers up the waste materials which it is to carry 
away. Here also it surrenders its oxygen and picks 
up its load of carbon dioxide to carry back to the 
lungs. Without these capillaries the blood-vessels 



A network of blood capil¬ 
laries as they look under 
the microscope. Corpus¬ 
cles are seen in the blood 
stream 


THE CIRCULATION OF THE BLOOD 


97 


would resemble a water system for a city without any 
faucets where we could get water, or, better, the body 
would be like a city through which many railroads 
passed, but with no stations where the trains could 
stop. Trains full of food might pass through the city 
but none be unloaded. 

The three kinds of blood-vessels. —In case of an 
injury we may know from the way a wound bleeds 
which of the three kinds of blood-vessels have been 
cut. If the bleeding is slight, the blood coming but very 
slowly, we may conclude that only capillaries, or 
some of the smaller branches of veins and arteries, 
have been opened. 

If the blood flows more freely, but in a steady stream, 
a vein has been cut. But if the flow is free and the 
blood comes in spurts, then we may be certain that 
an artery has been severed, for each spurt represents 
the beating of the heart. 

Important facts to remember. — i. The blood 
is a great transportation system, something like 
the rivers and canals of a country. It carries 
the food to the parts where it is needed, bears 
oxygen to the tissues, and transports waste 
materials. Anything that interferes with the 
circulation of the blood hinders growth, health 
and strength. 

2. The circulation of the blood depends on the 
heart and arteries. To have a weak heart or 


98 


PHYSIOLOGY AND HYGIENE 


weak arteries means a poor circulation. Alco¬ 
hol interferes with the heart. Tobacco also is 
injurious to the heart. Doctors often speak of 
the “smoker’s heart,” meaning a heart whose 
action has been injured by the use of tobacco. 
When we expect athletes to be at their best we 
do not allow them to use either alcohol or to¬ 
bacco; then why should any person who wants 
to be at his best use them! 

Interesting things to do. —i. Locate your own 
pulse beat in the wrist and count the beats 
(i) when you first awaken in the morning; (2) 
when you are sitting quietly in the school room; 
(3) just after you have been running or playing 
hard. How many beats in one minute in each 
case? 

2. Learn to take the pulse beat of other people by 
counting the pulse of members of your family 
or your schoolmates. Can you locate pulse beats 
at other points than the wrist, as in the temple, 
or the throat? 

3. If your school has a good microscope you can 
see the corpuscles of the blood flow through the 
capillaries. This is what you will have to do: 
Capture a frog without injuring it. Have your 
teacher help you bind it comfortably down on 
a thin strip of board, through which a half-inch 
hole has been bored. Fasten one of the frog’s 


THE CIRCULATION OF THE BLOOD . 


99 


feet so that it will have the web directly over 
this hole. Now place the frog and board in such 
position on the microscope that you can look 
through the web of the foot. The wonderful 
sight you will behold will fully repay you for all 
the trouble. And the frog will not be injured 
if you handle it carefully. 

Questions to answer. —What is meant by the cir¬ 
culation of the blood? How long does it take for the 
blood to go the entire round of the body? What did 
the ancients know about the circulation of the blood? 
Tell about the discovery of the English scientist, 
Harvey. Explain how the blood acts as a transporta¬ 
tion system for the body. What work does the heart 
do? Describe the chambers of the heart. How many 
times does the heart beat in a minute? What are the 
arteries and what is their use? What are the veins 
and what is their use? What are the capillaries and 
what is their use? Describe an experiment by which 
one can see the corpuscles flowing through the capil¬ 
laries. 

Health Problems 

1. Very old people or persons who are ill often have trouble 
to keep their feet warm. Why is this? 

2. Suppose the valves in the heart refuse to work, what would 
be the effect on the circulation of the blood? 

3. What rules for exercise or taking part in athletics can you 
give to protect the heart from overstrain and injury? 



CHAPTER XIV 


BLOOD AND LYMPH 

No doubt a puzzling question may have occurred to 
you as you read the last lesson. If the blood is all 
contained within a closed system of tubes which we 
call arteries, veins and capillaries, how does it deliver 
the food and oxygen it carries to the tissues outside 
the blood-vessels? How does the blood pick up the 
carbon dioxide and other waste products from the cells 
of our muscles and nerves if it does not come in contact 
with them? The capillaries do, as we have said, have 
thin walls, nevertheless they are all closed on their 
sides and no blood can get out. 

Let us see whether we can not best answer these 
questions by first asking another. Some time when 
you have received a slight scratch on the skin or had 
a piece of skin scraped off not deep enough to bring 
the blood, have you noticed a watery, colorless liquid 
oozing out? This fluid is called lymph. When we 
know just what lymph is and what it does I think we 
can answer the questions with which we started this 
chapter. 

An experiment. —A simple experiment will help us 
understand the nature of lymph. Go to the meat 
ioo 


BLOOD AND LYMPH ioi 

market and ask the butcher to give you a piece of thin 
animal tissue, such as the bladder or a part of the large 
intestines. Now fill a small glass with salt water and, 
having washed the tissue clean, tie it tightly over the 
top. Set the small glass inside a deep dish and fill 
the dish with fresh water. 

Let the glasses stand in this way for several hours. 
Then taste the water in the larger dish. You will 
find that it is distinctly salty. Remove the smaller 
glass and taste the water in it. You discover that it 
is less salty than when you put it in. Evidently the 
water in the two dishes has mixed. 

What has really happened is that the salt has 
passed through the animal tissue and mixed with the 
fresh water outside. This we call difusion . There 
are many substances that have the power to pass 
through animal tissues in this way. The white cor¬ 
puscles are able to crawl through the walls of the 
capillaries to the tissues outside, and then find 
their way back into the capillaries again. The 
oxygen from the air passes through, that is, diffuses 
through, the thin tissue of the air cells of the lungs 
and the walls of the capillaries of the lungs, and enters 
the red corpuscles of the blood. In the same way 
carbon dioxide passes from the blood out through the 
walls of the capillaries and the air cells and is ex¬ 
pelled from the body. 


102 PHYSIOLOGY AND HYGIENE 

« 

The lymph. —We are now ready to understand how 
this principle applies to the blood and the lymph. 
The plasma, as we have seen, is the liquid part of the 
blood. Certain fluids of the plasma are constantly 
passing through the walls of the capillaries, carrying 
with them the food materials for the tissues and the 
oxygen which has been set free from the red corpuscles. 
Since the red corpuscles can not pass through the walls 
of the capillaries, the watery liquid, or lymph , found 
outside the blood-vessels is nearly colorless. 

Every tissue of the body, in fact, every cell, is con¬ 
stantly bathed by the lymph. From the lymph the 
tissues select the food substances they need and 
appropriate them. Muscles, bones, nerves—each takes 
the materials required to build up its tissues. From 
the lymph the oxygen is taken for the use of the cells. 
Into the lymph are thrown the carbon dioxide and other 
waste materials to be removed. 

Just as fluid of the plasma finds its way out through 
the walls of the capillaries and mingles with the lymph, 
so fluid of the lymph finally passes through their walls 
back into the capillaries. A constant exchange is 
therefore going on between the plasma and the lymph, 
and yet plasma and lymph are never just alike. What¬ 
ever the blood contains of materials needed by the 
tissues goes over into the lymph. Substances that 
the tissues are through with and that should go into 
the blood to be disposed of go from the lymph 


BLOOD AND LYMPH 


103 


into the blood-vessels. It is clear that the lymph plays 
an important part as a carrier between the blood and 
the tissues. 

The circulation of the lymph. —The lymph is 
contained partly in open spaces among the tissues, and 
partly in a system of very 
thin-walled vessels. The ves¬ 
sels carrying the lymph are 
very irregular in shape, and 
the movement of the lymph 
in them is much slower than 
that of the blood in the veins 
and arteries. 

Like the system of veins for 
the blood, the smaller lymph 
vessels keep uniting to form 
larger ones. Like the blood 
in the veins, also, the lymph 
tends to flow back toward the 
heart. The large trunk of the 
lymphatic vessels, called the 
thoracic duct, finally opens in¬ 
to a great vein near the heart, where the lymph is 
poured directly into the blood circulation. 

The flow of the lymph is helped along by the action 
of the muscles. When muscles contract and expand 
they drive forward the lymph which is in contact with 
them. It is evident, then, that muscular exercise will 




104 PHYSIOLOGY AND HYGIENE 

help the lymphatic circulation just as it will aid the 
circulation of the blood. 

Massaging also aids the flow of lymph. In mas¬ 
saging, the pressing, kneading and squeezing of the 
muscles should be in the direction in which the lymph 
is flowing—that is, toward the heart. By this action 
the lymph is moved along more rapidly, thus washing 
the tissues of waste and bringing them food ma¬ 
terials. 

Lymphatic glands. —Scattered here and there 
along the lymphatic vessels are small glands , most of 
them much smaller than a pea. These glands serve 
as filters to remove poisons from the lymph. When 
they do this they sometimes swell up and become sore. 
For example, blood poisoning or a very severe sore on 
the hand may cause small knots or “kernels” to swell 
along the arm, or especially in the arm-pit, where 
there is a large collection of lymphatic glands. 

Tuberculosis, or even a severe cold, sometimes 
affects the lymphatic glands of the throat and neck, 
causing them to swell and become very sore. These 
glands may even break down and discharge pus, and 
have to be removed by the surgeon. Any sore lumps 
or “kernels” about the throat or neck should be shown 
the doctor at once. 

Important points to remember. — i. We have 
two distinct systems of circulation of life-giving 


BLOOD AND LYMPH 105 

fluids in the body, (1) the circulation of the blood , 
and (2) the circulation of the lymph . 

2. The blood circulation is in a closed system , 
consisting of the heart, the arteries, the veins 
and the capillaries. There is no opening nor 
outlet from this system unless the blood-vessels 
be injured by accident or destroyed by disease. 

3. The lymphatic circulation is carried on partly 
by a movement of the lymph in direct contact 
with the tissues, and partly within a system of 
very thin, irregular vessels called lymphatics , 
which lead toward the heart. 

4. These two systems of circulation are equally im¬ 
portant; neither would be complete without 
the other. The aggregate amount of the lymph 
is considerably greater than the amount of blood. 
The body of a person who weighs one hundred 
pounds contains about six pounds of blood, but 
about twenty-five pounds of lymph. 

5. Vigorous exercise is good for either system of 
circulation. The work or the play that causes 
the heart to beat strongly and drive the blood 
coursing through the veins and arteries, also 
hastens the flow of lymph among the tissues. 

Questions to answer. —What is lymph? Where is 
lymph found? What work is done by the lymph? 
Describe an experiment which explains how the lymph 
can pass through the walls of the blood-vessels. Why 


io6 


PHYSIOLOGY AND HYGIENE 


is the lymph not red like the blood in the veins and 
arteries? In what direction does the lymph constantly 
flow? What carries the lymph back toward the heart? 
What is the effect of massage upon the flow of the 
lymph? What are the lymphatic glands , and where 
are they found? What trouble sometimes affects lym¬ 
phatic glands? About how much lymph is there in 
the body of a person who weighs one hundred pounds? 
How much blood? 

Health Problems 

1. Have you ever known persons to have glandular swellings 
in their necks? What is the cause of these swellings? The 
treatment? 

2. Explain how physical exercise helps the flow of the lymph. 

3. Explain how free movement of the lymph helps recovery 
from fatigue. 

4. Janet was not well, and had become so tired and cross that 
she could not go to sleep. Her mother gently massaged 
her, and then she quietly fell to sleep. Explain what the 
massage did for her. 

5. A man who had been bitten on the finger by a rattlesnake 
immediately cut off his finger. The doctor said this saved 
his life. Explain how that could be. 

6. In what direction is the lymph flowing in the vessels, shown 
in the drawing on page 103? 

7 Explain how a sore on the hand may cause painful “kernels’' 
to swell in the armpit. 


CHAPTER XV 


BREATHING 

Breathing looks so simple and natural that it seems 
to require no explanation. Yet breathing is not so 
simple as it appears when you watch the baby’s breast 
rise and fall with each breath as it lies asleep. 

To understand how the lungs work in breathing 
suppose you make the following tests: 

1. Place your hands against your chest while you 
breathe slowly and deeply several times. Do 
you find your chest growing larger with each 
breath you take in and smaller with each breath 
you give out? Do the ribs lift upward somewhat 
in front as your chest expands and drop again 
as it decreases in size? 

2. Again, place your hands against your body just 
below the ribs while you breathe slowly and 
deeply. Do you find your body contracting and 
expanding at this point also as you breathe? 

How we inhale. —To breathe air into the lungs is 
to inhale; to breathe it out is to exhale. The process 
of breathing is called respiration. Let us first see how 
we inhale. 

107 


108 PHYSIOLOGY AND HYGIENE 

In order that we may take air into the lungs the 
lungs must of course expand; the space which they 
fill inside the chest must become larger. This is partly 

brought about by 
the lifting of the 
ribs by means of 
muscles which are 
attached to them. 
When you eat pork 
“spare ribs” you 
are eating the cos¬ 
tal muscles by 
means of which the 
pig's breathing 
was accomplished. 
Your costal mus¬ 
cles are attached 
in similar fashion 
to your ribs. 

But the chest 
cavity grows larger 
downward as well 

shows the branching of the bronchial tube in the as Outward. Let 

left lun s us see how this is 

accomplished. Just beneath the lungs and the heart 
is a muscular floor or partition upon which these organs 
rest and which separates them from the stomach and 
other organs of the lower part of the body. This 



BREATHING 


109 


floor is called the diaphragvi. The diaphragm is not 
stretched straight across the body cavity, but is curved 
upward like a dome. 

At each taking in of the breath the muscles of the 
diaphragm contract and pull the top of the dome 
downward, so that more room is left for the lungs 
above. This naturally presses down on the stomach 
and the other organs below the diaphragm, causing 
the expansion which you feel in your body at this 
point when you inhale. 

The lungs are very elastic. When the muscles of 
the ribs and the diaphragm have acted to make the 
space for the lungs greater, they must at once expand 
in order to fill this space. The air then rushes in and 
fills the spaces in the lungs. This is what we mean 
by inhaling. 

How we exhale. —Once the air has got into the 
lungs it stays like water in a sponge, until it is forced 
out. To force the air out of the lungs, or exhale, is a 
very simple matter. The muscles of the ribs relax 
and allow the ribs to settle back into place; the dia¬ 
phragm also relaxes and it again takes its dome shape. 
In this way the chest cavity is made smaller and the 
elastic lungs will squeeze out the air inside them 
exactly as we would press the water from a sponge. 

A simple experiment will enable one to see just how 
the muscles work in inhaling and exhaling: 



IIO PHYSIOLOGY AND HYGIENE 

I. Breathe your lungs very full of air and then hold 
your breath for a few moments. You will note 


No trouble about deep breathing here. These Boy Scout campers are taking 
an early morning exercise in correct breathing 

that to “hold the breath” is to hold the muscles 
of the chest and the diaphragm tense so that 
the walls are not allowed to settle back and press 
the air out of the lungs. 

2. Now exhale all the air you can from your lungs 
and again hold your breath, this time with your 







BREATHING 


III 


lungs as empty as you can make them. You 
find to '‘hold your breath” in this way you 
merely keep the muscles from lifting the ribs or 
pulling the diaphragm downward. Nor can you 
breathe in until you have allowed the muscles 
to make room for the lungs by enlarging the 
chest cavity. 

Shallow and deep breathing. —Good breathing 
requires that the lungs shall have room to expand both 
outward and downward. The chest must grow larger 
through the lifting of the ribs and also through the 
pressure downward of the diaphragm. Shallow breath¬ 
ing requires but little movement of the diaphragm. 

Bad habits about breathing. —The very first 
thing a baby does when it comes into the world is to 
breathe. It does not have to learn how; it knows. 
But in spite of this, many people as they grow older 
need to learn how to breathe; for very few grown 
persons breathe as well as babies. 

I. Few persons breathe deeply enough. It is 
possible that you do not. Suppose you make 
this experiment: Try breathing rather quick and 
not very deep, using just the ribs. You will 
find that you can breathe in this way without 
feeling any particular discomfort. Now notice 
occasionally whether you have this habit of 
shallow breathing. 


PHYSIOLOGY AND HYGIENE 


112 


2 . 


3 - 


Learning to breathe 
right. —There are two 
different ways in which 
we may make sure of 

deep breathing: Th e natural shape of the chest—larger 

I. We may practise at the base than the top, thus giving 

taking ten or twen- room for the lungs and other organs 

ty deep, full breaths in open air several times each 
day. But to do this successfully we shall need to 
have some system about it so that we shall not 
overlook it. One good way is to practise deep 
breathing just before going to bed, and the first 
thing when we get up in the morning—but al- 



Many do breathe in this way most of the time. 
Their breathing is shallow; they do not use 
their diaphragms sufficiently, and therefore the 
lungs are not expanded to their full extent. The 
air in the lungs is not properly changed, and 
this favors the growth of disease germs. 

It is in little used 
lung tissue that 
tuberculosis gets 
its start. We all 
need to learn to 
breathe deep, so 
that every part of 
our lungs shall be 
kept in use. 


The natural shape of the chest—larger 
at the base than the top, thus giving 
room for the lungs and other organs 


BREATHING 


113 

ways with open windows; also when we first 
leave the school room at noon or recess time. 
In deep breathing exercises we should breathe 
in slowly, steadily , deeply until the lungs are 
full as they will hold; and then let the air out 
as slowly as we took it in. 

2. We may make sure of deep breathing by taking 
free, active exercise in the open air. Each day 
we should have some form of exercise or play 
that sets our hearts to throbbing and drives our 
lungs to their fullest capacity. 

Especially is it necessary for those who are 
shut in most of the day, as pupils in school, to 
make sure of deep breathing through set exer¬ 
cises and through active work or play out-of- 
doors. 

Clothing that interferes with breathing. —It is 

impossible to breathe properly when the chest or 
lower part of the body is bound about with tight 
clothing. Tight waists, corsets, belts or any other 
articles of dress which hinder the full and free action 
of the lungs mean short breath, poor circulation and 
unused lung tissue. 

Posture and breathing. —Probably there are even 
more people who injure their breathing by cramped 
postures than by tight clothing. Suppose you try 
these experiments: 


PHYSIOLOGY AND HYGIENE 


114 

1. Take a glance about 
your school room and 
note how many boys 
and girls are leaning 
forward in a cramped 
position over the 
desk. Also how many 
have slouched down 
in the seat so that 
the body is bent in 
a curve. 

2. Now while you are 
sitting upright 
(standing would be 
better) in a good 
position breathe deep, 
and at the same time watch the feeling of ex¬ 
pansion in yourj chest. Next, sit bent forward 
cramped over your desk and while in this posi¬ 
tion try breathing deep. Do you get full chest 
expansion and deep breathing? Then try sliding 
down in your seat with your body cramped and 
curved, and again try filling your lungs very 
full of air. How do you succeed? What do you 
conclude about good posture and deep breathing? 

3. When you go to bed, try the same experiment of 
deep breathing, (1) while lying easily on your 
side with the body straight, and (2) with your 



The unnatural shape of the chest 
caused by tight corsets. The organs 
are cramped and unable to do their 
full work 



BREATHING 115 

body curled up in a ball. Which position do 
you conclude is best for sleeping? 

Questions to answer. —Describe an experiment by 
which you can watch your chest expand and contract 
as you breathe. What does it mean to inhale? What 
does it mean to exhale? What longer word is some¬ 
times used for the act of breathing? Explain the means 
by which the chest cavity is made larger each time we 
inhale. How is the cavity made smaller when we 
exhale? What is meant by shallow breathing? What 
is meant by deep breathing? Why should one learn 
to breathe deep? Explain two different ways in which 
we can make sure of deep breathing. Tell how tight 
clothing interferes with breathing. Explain how a 
stooped or cramped posture interferes with good 
breathing. 

Health Problems 

1. Point out each organ or part that has to do with breathing., 
Which of these are especially subject to disease? 

2. Explain the act of coughing; of sneezing. What causes 
each? 

3. Demonstrate the difference between shallow and deep 
breathing. 

4. Where does the mucous come from which you cough up 
when you have a cold? Why does the nose run? 

5. Try deep breathing while you are sitting stooped over. 
What do you conclude? 

6. How much of your lung tissue do you suppose you fail to 
use in your breathing? 


CHAPTER XVI 


THE WORK OF THE LUNGS 

The lungs are the lightest for their size of any organs 
of the body. They easily float in water. The lungs of 
animals are often spoken of as 1 flights/' because they 
weigh so little. 

It is because of the large number of air cells they 
contain that the lungs are so light in weight. In fact, 
the lungs are little more than great bags arranged to 
hold a considerable quantity of air and at the same time 
accommodate many blood-vessels. We can best under¬ 
stand the work of the lungs by first taking a look at 
their structure. 

Air tubes leading to the lungs. —If you will feel 
with your finger and thumb at the front of your throat 
you can trace a rough, ribbed tube which leads from 
the voice box down into the chest. This is the wind¬ 
pipe, or trachea. Just back of the top of the breast 
bone the trachea divides into two branches, one of 
which goes to each lung. These two branches are 
called bronchi , or bronchial tubes. 

The bronchial tubes keep on branching and re¬ 
branching after they enter the lungs, until very fine 
116 


THE WORK OF THE LUNGS 


ii 7 

air tubes have reached to every part of the lungs. 
Each of the little tubes finally ends in a cluster of 
tiny bulbs, called air cells . ' 

The whole arrangement of air tubes leading into the 
lungs very closely resembles an inverted tree, with 
hollow trunk, hollow branches and hollow twigs, and 
with hollow bulbs in¬ 
stead of leaves. 

The air cells. —It 

is in the air cells that 
the really important 
work of the lungs is 
done; for it is here 
that the air comes in 
contact with the blood 
and that the exchange 
of carbon dioxide for 
oxygen takes place. 

Each air cell is a 
very small chamber, but they number many thousands. 
So numerous are they that if the walls of the air cells 
from the lungs of an adult could all be spread out 
together they would cover a surface of about ten yards 
square. 

The walls of the cells are of very thin tissue, and im¬ 
bedded in this tissue are found numberless blood 
capillaries. All the blood of the body is pumped by 
the right ventricle through the capillaries around the 

9 



Air cells of the lungs, greatly magnified. 
The drawing shows the blood capillaries 
surrounding the one on the right 






Il8 PHYSIOLOGY AND HYGIENE 

air cells once in less than a minute, hour after hour 
throughout our lives. 

The exchange between air and blood. —The 

oxygen of the air and carbon dioxide are both 
gases that pass freely through the walls of the air 
chambers. Therefore when the blood comes surging 
into the lungs from the heart laden with carbon dioxide 
from the tissues, the exchange is quickly made. 
The oxygen passes through the walls of the air cham¬ 
bers to the red corpuscles of the blood, and the carbon 
dioxide passes out from the blood to the air cells. 

This exchange of carbon dioxide for oxygen is 
called purifying the blood. When the blood has handed 
its impurities over to the air cells and taken on a new 
supply of oxygen it is again ready for another tour of 
the body. 

Changing the air in the cells. —Try exhaling the 
air from your lungs as completely as you can, until 
you would think there was hardly a particle left. Yet, 
try as you will, almost half of the entire amount con¬ 
tained by the lungs remains in the air chambers and 
can not be forced out by breathing. 

In fact, in ordinary breathing only about one-tenth 
of the air in the lungs is changed with each breath.: 
As fresh air is inhaled it is mixed with the air already 
in the lungs, the change from stale air to fresh air 
being gradual. 


THE WORK OF THE LUNGS 119 

Fresh air for all the cells. —If only about one- 
tenth of the air in the cells is changed with each 
breath, it is clear that of the remaining nine-tenths, 
some must remain unchanged for a considerable time. 

Naturally the changes from stale to fresh air will go 
on most rapidly in the air chambers most used. If, 
because of tight clothing, bad postures or shallow 
breathing, we use only a portion of the lungs, the air 
in the little used cells remains impure. 

The little used air cells make good homes for the 
germs of tuberculosis. The doctors find that the dis¬ 
ease usually begins in the parts of the lungs which are 
least used. The germs can work in idle cells undis¬ 
turbed. 

Here are two important points to remember and 
put into practise: 

1. Little used lung tissue is always a source of 
danger. It is the natural home of the germs of 
colds, pneumonia and tuberculosis. 

2. To get the full use of our lungs and help make 
them safe from disease we must keep all the air 
cells employed. We must give the lungs plenty 
of room to breathe, and supply them with an 
abundance of fresh, clean air. 

How the lungs are protected against dust.— 

If you will stand before a mirror and carefully inves¬ 
tigate your nasal passages you will discover that they 
are lined with small hairs. If you could examine the 


120 


PHYSIOLOGY AND HYGIENE 


lining of the air tubes that lead to the lungs you would 
find them covered in like manner with thousands of 
tiny hairlike projections called cilia. 

The moist surfaces of the air passages catch the 
particles of dust, or any other foreign substance, and, 
by a peculiar wavelike motion toward the outside, 
the cilia drive the intruder out of the lungs. The 
hairs at the beginning of the nasal passages also serve 
to keep dust, small insects and the like from getting 
into the lungs. 

Dust an enemy of the lungs. —Dust is always an 
enemy of the lungs. The workers in certain dusty 
trades, such as stone cutting, grinding on emery wheels, 
manufacturing cement, etc., show a much higher 
tendency to lung diseases than the workers in dustless 
trades. Household dust and school room dust, espe¬ 
cially . in sunless rooms, is always to be avoided, 
while street dust may at times be quite dangerous. 

The first count against dust, as we learned in Book 
One, is that it carries bacteria. Millions of germs 
ride into the lungs on the dust particles breathed in 
as we work in a dusty place or sit in a dusty room. 
The great majority of these bacteria have already 
been killed by the sunlight; the most of those that 
are alive are harmless, but there is always the danger 
that there may be among them the living germs of 
disease. 

When dust of the heavier kinds, such as that coming 


THE WORK OF THE LUNGS 


121 


from stone, emery, or coal, is breathed in in large 
quantities the cilia find it impossible to drive it all out 
again. The .result is that these particles accumulate 
in the air cells of the lungs and interfere with their 
work. 

Doing away with dust. —Every one should declare 
war on dust. Many factories are now being equipped 
with machines that suck the dust up and drive it 
away from the workers. In other occupations work¬ 
men breathe through gauze, which strains the dust 
out of the air. Streets and roads are being oiled, and 
pavements washed to keep down the dust and save 
the lungs. 

We should be no less careful in our homes. Plush 
covered furniture and heavy curtains catch too much 
dust to be hygienic. Rugs which can be taken out 
and beaten are better than carpets. Carpet-sweepers 
are better than brooms, and vacuum cleaners better 
than either. Feather dusters and dry dusting-cloths 
should give way to oiled or damp dusting-cloths. Dust 
should not be allowed to gather on the tops of cup¬ 
boards, under furniture or in any unused corner, for 
every passing breeze whips it up into the air and it is 
soon lodged in the cells of our lungs. 

Lung power and physical strength. —One day I 

happened in at the gymnasium where a squad of 
college football men were being examined and measured 


122 PHYSIOLOGY AND HYGIENE 

by their trainer and coach. In the course of the testing 
each man stepped up to an interesting instrument 
called the spirometer, and, putting his lips to a mouth¬ 
piece, blew with all his might into the machine. A 
dial measured the number of cubic inches of air he had 
been able to force from his lungs. 

The trainer told me that if he 
could have but one measure of 
man’s physical power and en¬ 
durance he would test his lung 
capacity. “For,” he said, “no 
man’s muscles or nerves can be 
better than his lung power.” 
And that is in large measure 
true, although a man’s endur¬ 
ance depends also on his nervous 
system and on his heart. One 
might as well try to run his 
furnace without a draft to let 
the oxygen in to the fire as to try to run his body without 
lung capacity enough to supply oxygen for his tissues. 

Increasing our lung power. —From the lessons we 
have learned it is clear what we must do to have good 
lung power: We must train the muscles by which we do 
our breathing . 

The muscles by which we lift the ribs and expand 
the chest when we inhale can be strengthened by 
proper exercise so that they will be able to make the 



The appearance of the outer 
surface of the lungs 



THE WORK OF THE LUNGS 


123 


chest cavity larger and give the lungs more room. 
The muscles of the diaphragm by which the chest 
space is made deeper when we breathe can also be 
trained to greater power. 

These muscles, like all other muscles of the body, 
can be developed only through their proper use. These 
are the rules to be followed: 

1. Keep your chest up, head erect, body straight. 
Treat your lungs right; give them plenty of 
room and an abundance of fresh air. 

2. Train yourself to exercise properly. Play hard, 
work hard, get enough rest. Learn how to 
breathe, and then form the habit of breathing 
right while you work, play, rest or sleep. 

Interesting things to do. —1. If you have the 
use of a spirometer, practise blowing into it 
several times a week, keeping a record of your 
improvement. Note which members of the 
class make the best showing in lung power, and 
which show the greatest improvement from week 
to week. 

2. While the spirometer tests are going on have 
your chest measure taken. Do not be satisfied 
unless you are showing improvement. 

Questions to answer. —Why are the lungs so 
much lighter than muscle? What is the air tube that 
leads from the back of the mouth to the lungs? Ex¬ 
plain the branching of this tube. Describe the air cells 


124 


PHYSIOLOGY AND HYGIENE 


of the lungs. What important work takes place in the 
air cells? How does the oxygen get from the air into 
the blood, and how does the carbon dioxide get from 
the blood out into the air cells? 

What proportion of the air in the lungs is it impos¬ 
sible to drive out by exhaling? What proportion of 
all the air in the lungs is changed at each breath? 
Why should we make sure to use all the air cells in 
every part of our lungs? What are the cilia? Explain 
how the cilia work to keep dust from getting into the 
lungs. Give two ways in which dust is bad for the 
lungs. How are factories trying to protect the workers 
from dust? What measure should we take in our 
homes to do away with dust? Tell what the machine 
called a spirometer is for. Why is lung capacity so 
important a thing for an athlete? Tell how we may 
increase our lung power. 

Health Problems 

1. What trades or occupations are especially dangerous to 
health because of the dust? 

2. What are some of the devices used to protect workers 
against dust? 

3. Pittsburgh and Chicago are known as smoky cities. What 
do you suppose is the color of the lungs of people who live 
constantly in these cities? 

4. Judging from your usual posture in sitting, standing and 
working, and from your habits of breathing, how much 
lung tissue do you think you have which you do not use? 


CHAPTER XVII 


nature’s food laboratories 

A friend of mine recently gave me a great treat. 
One day he invited me to go with him through an 
automobile factory where he is employed and see how 
automobiles are made. 

We watched the process step by step. We saw men 
take the steel, the wood, the rubber and other ma¬ 
terials and work upon them. Part by part we traced 
the automobile as its various pieces were passed through 
roaring, buzzing machines, until at last they came out 
complete and ready to go into the finished car. 

Then we followed these parts into the assembling 
room, where they are put together and the car made 
ready to run. Last, we got into one of the beautiful 
finished cars and were carried like magic, gliding over 
the city streets. Ever since that day I have felt like 
taking off my hat to a great factory every time I pass 
by one. For it seems so wonderful that the raw ma¬ 
terial from the forest and the mine can, by the skilful 
work that goes on in the factory, be made into a 
machine so lifelike as an automobile! 

125 


126 


PHYSIOLOGY AND HYGIENE 


The plant laboratories. —In this lesson I want 
to tell you about a kind of factories we all know about 
in a general way, and which are even more wonderful 
than any automobile factory. The factories I have in 
mind are small, but they exist all about us by thou¬ 
sands, yes, by millions. They continue their work day 
and night, year in and year out. The factories I mean 
are the plants , nature’s food laboratories, on which all 
men and animals depend finally for their food supply. 

Let us begin our story at the beginning, and we shall 
soon come back to the factory question. We have 
already learned in Book One that all of the body’s 
energy comes from the food we eat. We have seen 
how the body can no more secure energy for its move¬ 
ments and its heat without burning up food supply 
than the locomotive can find energy to pull its load 
without burning the coal to supply steam. 

Food energy and body energy. —As we look at 
the food—the potatoes, the bread, the meat—placed 
on our table for a meal, it seems strange that it should 
contain such a store of energy. The food appears to 
be lifeless and dead; it may even have been cooked 
and the cells of which it is composed been destroyed. 
Who would dream that such substances could provide 
the heat and driving power for the body or build up 
its tissues! Yet we know that our food contains 
energy locked up in its cells just as coal contains energy 
stored away in its molecules. 


NATURE’S FOOD LABORATORIES 


127 


A still more astonishing thing is this: The chemist 
tells us that the tissues of our bodies have in them no 
element or substance which is not also found in the 
air we breathe, the water that fills our lakes and 
rivers, and the soil under our feet. And yet more 
wonderful, he tells us that the material of which our 
bodies are made actually first comes from the air , water 
and soil; and that the energy which the body uses 
for its heat and its work originally comes from the " 
sun! 

Making the food energy ready for the body.— 

The puzzling question is how the body can gather up 
and make use of the substances that exist in the air, 
the soil and water. Or how it can appropriate energy 
coming from the sunlight. 

For our bodies are made up of living cells; and no 
animal in the world is able to transform the lifeless 
food substances from the form in which they are found 
in soil, air or water into living tissues. No animal is 
able to take the energy needed by its body directly 
from the sunlight. There must first be some way of 
making these substances over, and fitting them for the 
use of living bodies. 

The work of the plants. —It is at this point that 
the plant laboratories come in. Plants have the power 
to take and use the energy directly from the sunlight. 
They are able to gather up the food elements from the 


128 


PHYSIOLOGY AND HYGIENE 


soil , the air and water , and work them over in such a 
way that these substances are built into the living cells 
of the plant. 

Plants are therefore chemical laboratories, busy at 
work preparing food for animals and men. The plants 



These Girl Scouts are making the cow furnish them food, but the cow was 
obliged first to secure this food from plants 


get the energy by which they carry on their work 
directly from the sunlight in which they grow. By the 
use of this energy they are able to pick up their food 
from the soil, the air and water, where it has been pre¬ 
pared for them by the myriads of useful bacteria of the 
soil and water. Thus they build up their own growth. 
When this is accomplished men or animals can eat the 




NATURE’S FOOD LABORATORIES 129 

plants, and so secure the materials they need for their 
bodies. 

Our dependence on plants. —If for any reason all 
the food plants should die or fail for a time to do their 
work, every animal on the face of the earth would soon 
die of starvation. So we cultivate plants. We go out 
into our gardens and plant our potatoes, beans and 
peas; we go out into the fields and sow our wheat. 
We give them rich soil, plenty of water, air and sun¬ 
shine. In a few weeks or months the plants we have 
tended will have gathered up rich treasures of food 
material which we could never obtain without their 
help. 

No wonder then that we try to improve our science 
of agriculture! No wonder that we study gardening 
and fruit growing! No wonder that we fight weeds, 
bugs and other enemies of our food plants! For 
whether we eat animals or plants, it matters not; we 
must finally go back to nature for our food. And we 
must have the plants to make our food ready for us. 

These two important facts are worth remembering: 

1. All the substance that goes to make up our 
bodies—the materials that build our muscles, 
bones, blood, and even our brains—first exists 
as inanimate matter in earth, air and water. 
And all the energy the body uses first comes 
from the sunlight. 

2. This lifeless material must be gathered by grow- 


PHYSIOLOGY AND HYGIENE 


130 

ing plants, and by them made over into living 
tissues. We may then either eat the plants, or 
eat the flesh of animals that live upon the plants. 

Interesting problems and experiments. —1. Set 

a growing plant away in a dark place for a week, 



These boys have been helping nature prepare their food in 
plant laboratories 


then note its appearance. Does it look healthy? 
Has it made a good growth? The poor showing 
made by the plant is due to the fact that it lacked 
the energy supplied by sunlight. Without this 
energy it was unable to take and use sufficient 
food from the soil, the air and water. A plant 
starves when away from sunlight. Since the 






NATURE’S FOOD LABORATORIES 


131 

plants store up the energy of sunlight for us, 
men can live for months in the dark and have 
good health if their food is good. 

2. On some near-by field notice the small, spindling 
stalks of grain growing on a hilltop; and note 
also the larger, stronger stalks produced on the 
lower ground. The difference is caused by the 
rains carrying the food elements of the soil from 
the hilltop to the plain below. The plants on 
the hilltop are suffering for want of food; those 
lower down have good nutrition. Good and poor 
nourishment will have a similar effect on people. 

3. Find some wet place in a field of grain or a 
garden where the water has been standing about 
the roots of the plants for several days following 
a rain. Explain why the plants look yellow and 
unhealthy (remember the plant's need of air). 
Is air as necessary to our life as to the life of 
plants? 

4. Let a house plant go without watering for a 
number of days, and then note its appearance. 
The plant has become thirsty. Do thirsty plants 
thrive? Is plenty of water as necessary to your 
growth as to the growth of a plant? 

Questions to answer. —Why are plants sometimes 
called laboratories or factories? Where does the body’s 
energy come from? Where does the food_ we eat 


132 


PHYSIOLOGY AND HYGIENE 


obtain its energy? Is the body able to gather its food 
energy directly from the air, the soil and water? 
Explain. What important work do plants do for men 
and animals? Explain what would happen to all 
animals in the world if plants should stop gathering 
energy and making it over into food. 

Health Problems 

1. You can take nuts, corn, olives and most other foods and 
extract from them oil which can be burned to produce heat 
and light. Where do the heat and light originally come 
from? 

2. Why is it necessary to apply some form of fertilizer to soil 
which is constantly producing crops? 

3. Why is it that growing animals and persons get hungry 
oftener than those who have their full growth? 

4. Cows’ milk has in it a great deal of sugar. Where does the 
sugar come from? 

5. China suffered a great famine in 1920-21 in which millions 
of people died of starvation. There was plenty of air, 
sunshine and soil. What was lacking which is necessary 
to produce food from the soil? 

6. Make a list of ten of the world’s chief food plants. What 
ones of these are raised in the United States? In your state? 
In China? In Russia? In England? 

7. Make a list of ten animals which are most important in 
supplying our food. What ones of these are produced in 

1 the countries just mentioned? 

8. Why do we not have famines in our country? 


CHAPTER XVIII 


KINDS OF FOOD REQUIRED 

A good way to begin the study of this lesson will be 
to write down the names of every different kind of 
food you have ever eaten. You will have in your list 
many kinds of vegetables, fruits, meats, cereals, nuts, 
dairy products, candies and so on. Besides all these 
there are no doubt many other foods which you have 
never yet tasted. 

In fact, if one should undertake to name all the 
various articles of food commonly used, he would have 
a list containing several hundred different varieties. 
Yet, aside from certain minerals and water, all these 
foods consist of only three different kinds of substances. 
These are: (i) proteins , (2) carbohydrates , and (3) fats. 

Three kinds of food material. —Proteins, carbo¬ 
hydrates, and fats are the three great classes of foods 
we must have in order to build up the tissues of our 
bodies, and supply the fuel and energy required. 

Nearly every kind of food we eat contains some pro¬ 
portion of all three of these substances. Yet some foods 
have more of one, and others more of another. For 
133 


10 


134 


PHYSIOLOGY AND HYGIENE 


example, lean meats and the white of eggs are almost 
pure protein and water. Bread, sugar and starch are 
principally carbohydrates. Butter, olive oil and cream 
consist chiefly of fats. 

Protein foods. —The proteins of our food were once 
the protoplasm of the living plants and animals from 
which the food comes. Since the growth and repair of 
our bodies depend on these proteins, a certain amount 
of protein food is therefore absolutely necessary. 
If the body is not supplied with the needed pro¬ 
tein, its cells will waste away and die. You may 
feed a growing person all you choose of sugar, starchy 
foods, and fats, but if the food contains too little pro¬ 
tein, his growth will be hindered and he will be sure 
to be under size. 

Carbohydrates and fats. —Carbohydrates and fats 
are the fuel foods of the body; they supply the heat and 
other forms of energy. Besides using them directly as 
a fuel the body has the power to store them up in 
layers of fat beneath the skin, or around the different 
organs. To do this it must of course first change the 
surplus carbohydrates over into fat. When, therefore, 
we eat more fuel foods than the body requires, the 
surplus is in this way stored up for future use. We 
say that a person who is thus storing up body fuel 
is growing fat. 


KINDS OF FOOD REQUIRED 


135 


Stored up fat has several different uses: 

1. It helps retain the body’s heat. This explains 
why a fat person usually can stand more cold 
than one who is thin. 

2. Fat provides padding, or cushions, which help 
protect the organs of the body from injury. A 
reasonable amount of fat also adds to one’s 
appearance. 

3. During a time of sickness or when one is working 
very hard and so using up energy faster than it 
is being supplied, the body can draw upon its 
supply of stored fat and use it for fuel. It is 
like having an extra bin of coal in the basement 
to use in an emergency. 

The uses of fat. —One who is drawing upon his 
reserve of fat always loses weight. The sunken ap¬ 
pearance of the eyes, when one has been ill or is severely 
exhausted, is caused by the using up of the cushions 
of fat which lie just behind the eyeballs. Football 
players often lose as much as five pounds in weight 
during a single game. The most of this is perspiration 
but some is fat which is used up rapidly by the hard 
exercise. 

It does the body no good to gather too much fat. 
Fat adds nothing directly to one’s strength. Fat per¬ 
sons are usually not quite as healthy as those of aver¬ 
age weight. Beyond a reasonable supply, fat may even 


136 PHYSIOLOGY AND HYGIENE 

hinder our movements, injure our appearance, and 
interfere with the work of the heart, lungs or other 
organs. 

When one grows too fat. — I met a man this morn¬ 
ing who is so fat that he must be uncomfortable. He 
wheezes when he hurries to catch a car. He waddles 
when he walks. His clothes look to be too small for 
him. His appearance would be much more attractive 
if he were to lose twenty-five or thirty pounds of fat. 

How does one grow too fat? Some fat persons are 
not quite well and can not use all the fat of their food. 
It therefore tends to accumulate in their bodies. But 
for most persons there are two reasons why they get 
fat: they may eat more than the body requires, or 
they may exercise so little that the body uses up but 
little of its fuel, and so allows the surplus to accumu¬ 
late as fat. If one who is otherwise well wants to 
reduce his surplus fat he can do it in either one of 
two ways: (i) eat less, especially of fat-producing 
foods, or (2) exercise more. 

The following table gives a few of the more common 
foods containing a large proportion of one of the three 
chief food materials. Some foods, as milk or eggs, 
have a good supply of two or more food substances: 


KINDS OF FOOD REQUIRED 


137 


Foods rich 

Foods rich 

Foods rich 

in Protein 

in Fat 

in Carbohydrate 

Lean meats 

Fat meats 

Most vegetables 

Fowl 

Eggs 

Bread 

Veal 

Nuts 

Potatoes 

Fish 

Butter 

Sugar 

Eggs 

Cream 

Milk 

Skim milk 

Cheese 

Fruits 

Beans 

Milk 

Oysters 

Peas 

Most pies 

Peas 

Lentils 

Doughnuts 

Beans 

Cheese 

Cream soups 

Peanuts 


Bulky foods. —Not only should our dietaries con¬ 
sist of the right food elements, but they should also 
possess considerable bulk. Many of our best foods 
are too concentrated. It is possible to compress enough 
meat and vegetables for a day’s rations into a very 
small package. Food in this form, however, does not 
serve its full purpose. 

We need daily a considerable quantity of foods that 
contain coarse, woody fiber. Such fruits and vege¬ 
tables as lettuce, celery, spinach, asparagus, cabbage, 
cauliflower, corn, beets, tomatoes, berries, etc., supply 
us the bulk and fiber we require. 

Hard foods. —It is necessary also that some pro¬ 
portion of our foods consist of hard substances that 
require cutting and grinding by the teeth. Hard 


138 


PHYSIOLOGY AND HYGIENE 


cereals, crusts of bread, hard biscuits, hard fruits, 
fibrous vegetables and nuts are a very important part 
of our diet. 

Hard foods are desirable because they require chew¬ 
ing and this helps to preserve the teeth and keeps 
them in good condition. Chewing also insures a flow 
of saliva in the mouth and of gastric juice in the 
stomach. 

Dry and crusty bread is therefore preferable to soft 
fresh bread or rolls, such as many people like. The 
physicians tell us that the Filipinos had perfect 
teeth so long as they lived on hard, coarse foods. But 
when they changed to the soft foods used by the more 
highly civilized nations, their teeth quickly began to 
decay. 

i. The table of foods which follows is only for 
reference. Look it over carefully and make a 
list: 

(1) Of the ten foods containing the largest pro¬ 
portion of protein; 

(2) Of the ten foods containing the largest pro¬ 
portion of carbohydrates; 

(3) Of the ten foods containing the largest pro¬ 
portion of fats; 

(4) Of the ten foods containing the largest pro¬ 
portion of water. 

Compare your lists with the table given on page 
139. Do they agree? 


2. 


KINDS OF FOOD REQUIRED 139 


Per Cent, of Food Substances in Different Articles of Diet: 



Protein 

Carbo¬ 

hydrate 

Fat 

Water 

Mineral 

Matter 

Almonds. 

21.0 

17-3 

54-9 

4.8 

2.0 

Fresh asparagus.:. 

1.8 

3-3 

0.2 

94.0 

0.7 

Bananas. 

i -3 

22.0 

0.6 

75-3 

0.8 

Dried beans. 

22.5 

59-6 

1.8 

12.6 

3-5 

Roast beef. 

22.3 

.... 

28.6 

48.2 

i -3 

Bread. 

8.9 

56.7 

4.1 

29.2 

1.1 

Butter. 

1.0 

.... 

85.0 

11.0 

3-0 

Fresh cabbage. 

1.6 

5-6 

0-3 

9 i -5 

1.0 

Sponge cake. 

6-3 

65-9 

10.7 

15-3 

1.8 

Cheese. 

25-9 

2.4 

33-7 

34-2 

3-8 

Chicken. 

21-5 

.... 

2.5 

74.8 

1.1 

Green corn. 

3 -i 

19.7 

1.1 

75-4 

0.7 

Oyster crackers. 

11 .3 

70.5 

10.5 

4.8 

2.9 

Fresh cranberries. 

0.4 

9.9 

0.6 

88.9 

0.2 

Egg. 

13-4 

.... 

10.5 

73-7 

1.0 

Wheat flour. 

13-8 

71.9 

i -9 

11.4 

1.0 

(Gingerbread. 

5-8 

63-5 

9.0 

18.8 

2.9 

Macaroni. 

13-4 

74.1 

0.9 

10.3 

1.3 

Leg of mutton. 

25.0 

.... 

22.6 

50-9 

1.2 

Milk. 

3-3 

5-0 

4.0 

87.0 

0.7 

Brazil nuts. 

17.0 

7.0 

66.8 

5-3 

3-9 

Oatmeal. 

16.1 

675 

7.2 

7-3 

1.9 

Fresh oysters. 

6.0 

3-3 

i -3 

88.3 

1.1 

Peanuts. 

25.8 

24.4 

38.6 

9.2 

2.0 

Dried peas. 

24.6 

62.0 

1.0 

9-5 

2.9 

Green peas. 

7.0 

16.9 

0-5 

74.6 

1.0 

Potatoes. 

2-5 

20.9 

0.1 

75-5 

1.0 

Squash pie. 

4-4 

21.7 

8.4 

64.2 

1-3 

Apple pie. 

3 -i 

42.8 

9.8 

42.5 

1.8 

Tapioca pudding. 

3-3 

28.2 

3-2 

64.5 

0.8 

Dried prunes. 

2.1 

73.3 

.... 

22.3 

2.3 

Rice. 

8.0 

79 0 

0.3 

12.3 

0.4 

Canned salmon. 

21.8 

.... 

12.1 

63-5 

2.6 

Fresh tomatoes. 

0.9 

3-9 

0.4 

94-3 

0.5 

Veal. 

21.2 

.... 

8.0 

70.3 

1 >0 

Soft-shell walnuts. 

16.6 

16.1 

63-4 

2.5 

1 -4 

















































140 


PHYSIOLOGY AND HYGIENE 


Questions to answer. —What can you tell about 
the number or variety of foods we commonly eat? 
Into how many classes may all these different foods 
be divided? What are the names of the three groups 
of foods? What is the work done by protein foods in 
the body? What do carbohydrates and fats do for 
the body? Give several uses of stored up fat. Tell 
why or how a person becomes fat. What happens to 
the fat of the body when one becomes thin, as in 
sickness? Name several different foods rich in each of 
the three food qualities, protein , fat , and carbohydrate . 
Why do we need bulky foods? Why do we need hard 
foods? 


Health Problems 

1. Since there is no place for body fat to come from but the 
food we eat, and since the body stores as fat only the food 
not required for other uses, what would you advise a person 
to do in order to keep from getting too fat? 

2. From what foods are you securing most of the proteins of 
your dietary? Most of the fats? Most of the carbohy¬ 
drates? 

3. If you were obliged to get along on three or four foods only, 
what ones should you choose (not because you like them 
best, but for their food elements) ? 

4. Suppose your food should not contain enough fat, what 
would be the effect? Enough protein? Enough carbohy¬ 
drates? 

5. Do you think you live on a well balanced dietary? Give 
reasons for your answer. 


CHAPTER XIX 


MEASURING FOOD VALUES 

If we should be asked how much we ate for dinner, 
we might tell how many slices of bread, how many 
eggs and how many helpings of potatoes we had. 

The scientists have invented a more accurate way, 
however, of measuring the food we eat. Just as dis¬ 
tance may be measured in yards, wheat in bushels, 
and temperature in degrees on a thermometer, so the 
amount of food we require may be measured in calories . 

Measuring food in calories. —A calory (kal'o ri) 
is the amount of heat required to raise the tempera¬ 
ture of one litre (practically one quart) of water, one 
degree centigrade. It is possible to measure food 
values in calories, because the body uses most of its 
food as fuel for producing, heat and other forms of 
energy. 

Instead, therefore, of saying that a person needs so 
many slices of bread, so many potatoes, or such and 
such a quantity of meat for a day’s ration, we may 
state that he requires a certain number of calories . 
One may secure the required number of calories from 
a great variety of foods, but he must have enough 
calories for fuel or his body will suffer. 

I4i 


142 


PHYSIOLOGY AND HYGIENE 


The number of calories we require. —Our bodies 
do not require the same amount of food under all con¬ 
ditions. Since the chief use of food is to act as fuel 
for the body, it is clear that weather will have some¬ 
thing to do with the quantity of food we need. You 
have perhaps noticed that you get more hungry in 
the winter than in the summer. This is on the same 
principle as that the furnace requires more coal in 
cold weather than in warmer weather. The body 
requires more fuel to heat it when the air about us is 
cold. Again you have noticed that when you are 
working or playing hard, you get more hungry than 
if you are not exercising. This is on the same principle 
as that the locomotive, when running sixty miles an 
hour, will require more coal than when running thirty 
miles an hour. The body uses up more fuel energy 
when it is active than when it is at rest. 

Careful experiments have shown that a man of 
average size, who is engaged in such work as a trade, 
or farming, requires from 2,500 to 3,000 calories of 
food a day. Women require somewhat less food than 
men, because they are smaller, and also because their 
work is generally not quite so active as the work of men. 

Boys and girls of twelve and thirteen years of age, who 
are having plenty of exercise, need about 2,000 calories 
of food a day. This means that your body is daily using 
up as much energy as would be required to bring 
eleven quarts of water from freezing to the boiling point. 


MEASURING FOOD VALUES 


143 


The value of different kinds of food. —When we 
speak of a certain kind of food being nourishing, or 
strengthening, we mean that it will supply a large 
amount of food energy to the body. A certain amount 
of it will yield a large number of calories. Some foods 
are much more concentrated than others, hence we 
need a smaller amount of them. 

An interesting comparison of different foods can 
be shown in the following way: Suppose you were to 
eat but one single kind of food for a day, and suppose 
you were to take just enough to supply 2,500 calories. 
Suppose that for the first day you decided to eat noth¬ 
ing but butter; fourteen ounces of butter would supply 
your 2,500 calories. The next day take almonds or 
walnuts. You would then need one pound . Suppose 
on the third day you were to choose lettuce. You 
must have thirty-five pounds of lettuce to obtain 
2,500 calories of food energy. 

Of course no one would think of eating in this way, 
but such an illustration makes it clear why we eat a 
larger quantity of certain foods than we do of other 
foods. The following table is not for you to commit 
to memory, but to look over carefully and compare 
the amount of nourishment in different kinds of foods. 
Remember that the weight given for each food is what 
you would have to eat if you chose that food alone 
from which to secure the 2,500 calories you would 
require each day if you were full grown. 


144 PHYSIOLOGY AND HYGIENE 

The following table shows the amount of each food 
that would be required to secure from it alone 2,500 
calories: 

Butter.14 ounces 

Almonds or walnuts. 1 pound 

Smoked bacon.18 ounces 

Cheese. pounds 

Raisins, dried figs or dates. 2 pounds 

Bread. 2 pounds 

Beef. 3 pounds 

Baked beans. 5 pounds 

Eggs (about 38 eggs). 5 pounds 

Bananas. 7 pounds 

Potatoes. 8 pounds 

Fish.7 to 13 pounds 

Milk. 9 K pounds 

Apples.10 pounds 

Oysters.13 pounds 

Onions.14 pounds 

Cabbage.21 pounds 

Tomatoes.30 pounds 

Lettuce.35 pounds 

(From Bulletin 29, U. S. Dept, of Agriculture.) 

This interesting table shows that to get the amount 
of fuel which fourteen ounces of butter would give, 





















MEASURING FOOD VALUES 


145 


Protein. 

Bum 



Carbohydrates 


Fuel Value 


FOOD MATERIALS 

Price 

per 

pound 

~W 

.cents 

will 

buy 

Pounds of nutrients and calories of itn*l value in 
20 cents worth 

Cents 

lbs. 

1 lb 2 lbs l lbs 

2000 Calories 4000 Calories 6000 Calories 

Beef, round 

28 

• 7 4 









m 


Beef, sirloin 

40 

.50 

i 


Beef, shoulder 

« 

24 

.83 

m 


Mutton f leg 

32 

.63 

m 


Pork, Loin 

24 

.S3 

Hi 


Pork, salt, fat 

24 

.83 



Ham, smoked 

36 

.56 

w 

■nn 

Codfish, fresh, dressed 

20 

1.00 

i 


Codfish, salted 

14 

1.43 

Hi 


Oysters, 70 cents quart 

36 

.56 



Milk, 12 cents quart 

6 

3.33 

iiW 


Butter 

50 

.40 



Cheese 

32 

.63 

wm 


Eggs, 24 cents dozen 

32 

.63 

i 


Wheat bread 

10 

2.00 



Wheat flour 

6 


. . . 


Com meal 

5 


mt t mmrnmmmmmmmmm&ti 7 



Oat meal 

8 


.. 

, CO 


Beans, white, dried 

10 


mmmmmm .. 



Rice 

16 


| 

; 



Potatoes 1.20 bushel 

2 


W WMMtMMim . ..... .. .. 



Sugar 

12 . 






This table shows the relative value of different foods at the prices 
usually charged. It also indicates the amount of the different food 
elements in each kind of food 
















































































146 


PHYSIOLOGY AND HYGIENE 


one would have to eat more than three dozen eggs; 
or drink nine and a half pounds of milk; or eat eight 
pounds of potatoes; or thirteen pounds of oysters; or 
thirty pounds of tomatoes. 

It is easy to see from this comparison why it is better 
to have a varied diet. Butter gives its fuel in too con¬ 
centrated a form, while most vegetables, and even 
oysters, would be required in too great quantities if 
eaten alone. 

Interesting questions and problems. —1. Why 

does an active boy or girl get more hungry than 
an adult? 

2. Which will require more food, a man who is 
digging a ditch or a man who is working in a 
store? Explain why. 

3. What difference should we make in the amount 
of fats and carbohydrates in our diet as the 
season passes from winter to summer? What 
difference in the amount of food we take? Why 
do the Esquimos like whale blubber and other 
fat meats, while people who live in the tropics 
prefer foods containing less fat? 

4. Study the table that follows and estimate the 
number of food calories you are eating from 
day to day. Make a list of the articles of food 
you eat for one day, and estimate the number 
of calories you receive from each kind of food. 


MEASURING FOOD VALUES 147 

The quantities given for each of the following foods 
will yield 100 calories. 


Name of food 


Portion required for ioo calories 


Weight required 
for 100 calories 


Beans, canned. 

Beans, string. 

Beets, cooked. 

Sweet corn. 

Onions, cooked. 

Peas, green. 

Peas, canned. 

Potatoes. 

Tomatoes, fresh. 

Apples. 

Bananas. 

Oranges. 

Peaches. 

Beef, round, fat. 

Beef, round, lean. 

Lamb chop. 

Pork, roast. 

Cake, chocolate layer.. . 

Doughnuts. 

Pie, apple. 

Pudding, brown betty. . 
Pudding, cream rice.... 

Bread. 

Corn flakes, toasted.... 

Oatmeal. 

Rice. 

Shredded wheat. 

Butter. 

Milk, skimmed. 

Milk, whole. 

Sugar, granulated. 

Eggs.. 


Small side dish. 

Five servings. 

Three servings. 

One side dish. 

Two large servings. 

One serving. 

Two servings. 

One good sized. 

Four average sized. 

Two. 

One large. 

One very large. 

Three average size. 

Small serving. 

Large serving. 

One small. 

Small serving. 

Half ordinary piece. 

Half a doughnut. 

One third ordinary piece 
Half ordinary serving... 

Very small serving. 

Ordinary thick slice. 

Ordinary cereal dish full 
One and a half servings. 
Ordinary cereal dish full 

One biscuit. 

Ordinary pat, or ball 
One and a half glasses... 

Small glass. 

Three teaspoonfuls. 

One large. 


2.66 ounces 

16.66 

ounces 

8.7 

ounces 

3-5 

ounces 

8.4 

ounces 

3 . 

ounces 

6-3 

ounces 

3-5 

ounces 

15 . 

ounces 

7-3 

ounces 

3-5 

ounces 

9-4 

ounces 

10. 

ounces 

1-3 

ounces 

2.2 

ounces 

.96 ounces 

1. 

ounce 

.98 ounces 

.8 

ounces 

1.1 

ounces 

2. 

ounces 

2.65 ounces 

1 -5 

ounces 

.97 ounces 

5-6 

ounces 

3-1 

ounces 

.94 ounces 

.44 ounces 

9.4 

ounces 

4-9 

ounces 

.86 ounces 

2.1 

ounces 


—Adapted from Fisher and Fisk, How 10 Live . 





































































148 


PHYSIOLOGY AND HYGIENE 


Questions to answer. —What is the name of the 
measure used for food values? What is a calory? Why 
does one need more food in winter than in summer? 
Why does one need more food when he is at work 
than when he is idle? About how many calories of 
food does a full-grown person engaged in moderate 
work require in a day? Name several foods a small 
quantity of which will supply, many calories. Name 
other foods a large quantity of which is required to 
supply enough calories. Explain why it is better to 
have a varied diet than to eat all one kind of food. 
How many calories of food should a boy or girl of 
twelve or thirteen years eat each day? 

Is your weight proportioned to your height? 


(Indoor clothes, but without shoes) 


BOYS 


GIRLS 


Average Weight 

10% 



Average Weight 

10% 

Height 

for Height 

Underweight 


Height 

for Height 

Underweight 

Inches 

Pounds 

Pounds • 


Inches 

Pounds 

Pounds 

52 

65.8 

59*2 


52 - 

63.8 

57*4 

53 

68.9 

62.0 


53 , 

66.8 

60.1 

54 

72.0 

64.8 


54 

70.3 

63.3 • 

55 

75-4 

67.9 


55 

74*5 

67.1 . 

56 

79.2 

71*3 


56 

78.4 

70.6 

57 

82.8 

74*5 


57 

82.5 

74*3 

58 

87.0 

78.3 


58 

86.6 

77*9 

59 

9 i 1 

82.0 


59 

91.1 

82.0 

60 

95.2 

85.7 


60 

96.7 

87.0 

61 

99-3 

89.4 


61 

102.5 

92.2 

62 

103.8 

93*4 


62 

no.4 

99*4 

63 

108.0 

97.2 


63 

118.0 

106. 2 

64 

II 4-7 

103.2 


64 

123.0 

no.7 . 

65 

121.8 

109.6 


65 

130.0 

117.0 

66 

127.8 

ii 5 *o 


66 

137.0 

123.3 

67 

132.6 

1 19 * 3 


67 

143*0 

128.7 

68 

138.9 

125.0 


68 

146.9 

132.2 















CHAPTER XX 


WHY WE COOK OUR FOOD 

Yesterday I sat in a restaurant near three men who 
were ordering their dinners. One man asked for roast 
beef, another for beef stew, and the third for a broiled 
steak. They all ordered beef, but each wanted his 
beef cooked in a different way. 

When it came to potatoes it was the same. The 
first man ordered his potatoes baked; the second asked 
for his hashed brown; the third wanted his mashed. 
Again the same food, but three different ways of cook¬ 
ing it. 

The importance of good cooking.—The cooking 
of food is one of the most important arts known in our 
civilization. Not only do most girls learn to cook in 
their homes, but our best schools are now giving 
courses in cooking so that all may become experts at 
it. It is well for even boys to know the simpler forms 
of cooking. In fact, the Boy Scout organization con¬ 
siders a knowledge of cooking so important that it 
requires its members to be able to cook in an appetizing 
way a number of simple dishes. 

Poor cooking wastes food, endangers health, and 

11 149 


150 PHYSIOLOGY AND HYGIENE 

makes what we eat less palatable. Good cooking is 
so important that large hotels often pay their chief 
cooks larger salaries than are received by bank clerks, 
doctors or lawyers. 

Why we cook our food.—There are five important 

reasons why we cook most of our food: 

1. Cooking softens the food and breaks up its tis¬ 
sues so that they are more easily chewed and 
digested. Meats, most vegetables, and the 
harder fruits, especially, require cooking. Nearly 
all cereal grains are also cooked before being 
eaten. 

2. Cooking causes certain chemical changes in 
some foods, making them easier to digest. For 
example, cooking green apples or other unripe 
fruits changes the starch into sugar. If fruit 
is eaten green the stomach must do the work of 
changing the extra starch into sugar. Not in¬ 
frequently this proves more than the stomach 
is able to do, and indigestion follows. 

3. Most foods have a better flavor, and are more 
palatable when they are cooked. For example, 
most of us would not care to eat raw flour, or 
uncooked meats, potatoes, or other vegetables. 
We not only want our foods cooked, but want 
them cooked in the particular way that we 
happen to like best. 


WHY WE COOK OUR FOOD 


151 

4. Cooking kills many injurious germs found in 
certain foods. Most germs are killed by boiling, 
and all by oven heat sufficient for baking bread 
or meats. We learned in Book One, that it is 
sometimes necessary to boil even milk and 
water, in order to kill the germs of typhoid fever 
or other disease sometimes found in them. 

5. Cooking our food and serving it warm has the 
advantage of bringing it up to the temperature 
of the digestive organs. The stomach works 
better when it is not cooled too greatly by cold 
foods. 

How we shall cook our foods.—There is no one 
way to cook most foods which should take the place 
of all other ways. For example, potatoes can be cooked 
in at least a score of different ways. We have many 
recipes for cooking meats. Flour, and other forms of 
cereals, may be baked in the form of bread, rolls, cakes, 
or cookies, or prepared in many other ways. 

Yet there are some methods of cooking which in 
general are better than other methods. For example, 
broiling is usually better than frying any food. Broil¬ 
ing softens and breaks up the tissues of meats or vege¬ 
tables, while frying has the tendency to harden the 
tissues and make them more difficult both to chew 
and digest. Baking is a satisfactory way of cooking 
many kinds of foods. 



152 PHYSIOLOGY AND HYGIENE 

Some of our foods, as the cereal breakfast foods, are 
sometimes not cooked long enough. Oatmeal, cream 
of wheat and other such cereals should be cooked for 
not less than half an hour, and are better still if 
kept simmering for an hour or more before serving. 


Boy Scouts are expected to know how to cook 

Yet such cereals are often served with only a few 
minutes of cooking. 

Ready cooked foods.—Many different kinds of 
food now come to us already cooked. One can buy 
almost every kind of cereal ready cooked and put up 
in packages. Such prepared foods are scientifically 





WHY WE COOK OUR FOOD 


153 


cooked at the factory before being put in the package, 
and come to us ready to serve. We can even buy 
canned meats, fruits, vegetables, and soups ready 
cooked and only requiring to be warmed before 
being served. The baker also offers us a tempting 
array of bread, cakes, cookies, and pies. Most of the 
ready-to-serve food now sold in the best markets is 
well cooked. Nevertheless, the greater part of our 
food should be cooked in the home. And girls, espe¬ 
cially, should make it one of their chief ambitions to 
become good cooks. 

Foods which do not require cooking. —While 
we require most of our foods to be cooked, it is never¬ 
theless necessary that we have some food that is un¬ 
cooked. This is because there are certain parts or 
substances in foods called vitamins , some of which 
are destroyed by cooking. 

These vitamins are not well understood, but are 
known to be necessary to our health. It has been 
found that soldiers, sailors, or others obliged to live 
for some time upon canned or cooked foods, are af¬ 
fected with scurvy and other similar diseases. When 
they are given a diet including fresh fruits and vege¬ 
tables containing vitamins the diseases disappear. 

Our diet should therefore always contain such foods 
as lettuce, tomatoes, celery, fruits, nuts, and a reason¬ 
able proportion of milk. For these may be eaten raw, 
and the vitamins secured which are necessary to health. 


154 


PHYSIOLOGY AND HYGIENE 


Interesting things to do. — i. Make a list of the 
different foods which you eat, both raw and 
cooked. Another list of those you eat only when 
cooked. A third list of those you eat only raw. 

2. Write down all the different ways you know of 
cooking potatoes; apples; meat; eggs; flour; 
corn meal or oat meal. 

3. Make a list of the different dishes that you can 
cook. Are there others that you should learn 
to cook? Are you improving in your cooking? 

4. Do you know certain housekeepers whose bread, 
pies, cakes and other cooking always turn out 
just right? Do you know other housekeepers 
whose cooking is not so successful? Do you 
think it worth while to learn to be the very 
best cook possible? 

Questions to answer. —Give the case of the three 
men in the restaurant who wanted their food cooked 
differently. Why is the cooking of food so important? 
Give five important reasons why we cook our food. 
Explain why broiling is a better method of cooking 
meats than frying. What caution is given about the 
cooking of breakfast cereals? What is said about 
ready cooked foods to be found in the market? Why 
should we eat some uncooked foods? Mention several 
foods that may be eaten either cooked or raw. Cer¬ 
tain foods that are eaten always raw. Still other foods 
that are always cooked before they are eaten. 


CHAPTER XXI 


WATER AS FOOD 

Did you ever stop to think that when we buy certain 
foods we really purchase more water than real food 
substances! 

For example, let us refer again to the table on page 
139, which shows the proportion of water in different 
foods. Then if we will do a simple problem in arith¬ 
metic, we discover the following astounding facts: 

When we buy a gallon of milk, nearly three and 
a half of the four quarts we receive are water; 

When we purchase a bushel of potatoes, three 
of the four pecks are nothing but water. 

When we order a quart of oysters the dealer 
gives us considerably more than one and a half 
pints of water. 

When we bring home a dozen eggs, it takes nine 
to make up the amount of water in the twelve. 

Even a rich, savory piece of beef-steak is half 
water; and the meat of a chicken almost three- 
fourths water. 

Water needed for our own tissues. —Yet we 

need not be surprised that our food contains so much 


156 PHYSIOLOGY AND HYGIENE 

water. For we have already learned that our own 
tissues have in them a large proportion of water. 

The organs which perform the most important work 
of our bodies, as the brain, the liver, and the kidneys 
are by weight three-fourths water; the muscles are 
about the same proportion. The blood and the lymph 
are about nine-tenths water. Even the bones have 
a large amount of water in them. Taken altogether, 
there is sufficient water in our tissues to make up over 
two-thirds of our entire bodily weight. 

Uses of water in the body. —Our foods must con¬ 
tain a large proportion of water, therefore, because of 
the fact that the tissues of our bodies require so much 
water and because the body can not do its work with¬ 
out an abundance of water. 

For example, our joints must have water. Every 
joint where two bones work together is enclosed in a 
sack or bag. This sack is filled with a liquid which is 
chiefly water. Without this liquid the ends of the 
bones would work on each other like the bearings of 
a machine without oil. A farmer whom I know ran 
the tine of a pitchfork into his knee in such a way as 
to destroy the bag holding the ‘'joint water.’’ His 
knee has grown very stiff and he has almost lost the 
use of the joint. 

Organs that require water. —Water serves to 
protect and act as a lubricant for several important 
organs. The heart is surrounded by a loose sack 


WATER AS FOOD 


157 


called the pericardium , which contains a little watery 
liquid. The lungs are enveloped in a similar bag, 
called the pleura , which is kept moist by a water-like 
fluid. The brain is enclosed in a water-tight casing 
and is surrounded entirely by liquid. 

The skin, as we have already learned, regulates the 
heat of the body by the evaporation of water through 
the pores. As much as several quarts of water a day 
may be used in this way. 

Water necessary to the life of cells. —Not only 
do the organs require water for their work, but every 
single cell of the body requires water to continue its 
life; in fact, it is bathed on all sides by lymph, which is 
chiefly water. So necessary is water to the life of cells 
that, should the water be in some way dried out of our 
cells and tissues, they would immediately die. 

These facts help us to understand why one can live 
longer without nourishing foods than without water. 
For when we are obliged to go for a time without food, 
the body can use up the surplus of fat and other food 
substances which have been stored away in the tissues. 
But water can not be stored up for future use; there¬ 
fore we can live but a short time without it. 

No wonder, then, that thirst is so dreadful a thing 
when men are lost in a desert or adrift on the ocean, 
where no drinking water is to be had. For thirst is 
the protest of every organ, tissue and cell of the body 
against the injury that comes from lack of water! 


PHYSIOLOGY AND HYGIENE 


158 

Water obtained from foods. —A large part of the 
water we need comes directly from our foods, most of 
which, as we have seen, have much water in them. To 
the drier foods, such as the cereals, we add water in 



Still another use for water. Besides being so necessary with our food, water 
provides opportunity for clean sport and fun. Every boy and girl should 
learn to be at home in the water 


cooking. For example, each pound of rice as bought 
at the store comes to the table with about three pounds 
of water added. 

We also add water to vegetables and meat when we 
serve them in soup or with gravies. Fruits are cooked 
in water or else syrups, consisting largely of water, 




WATER AS FOOD 


159 

are used. When we drink milk, cocoa, tea or coffee 
we are, of course, drinking chiefly water. 

Drinking plenty of water. —But no matter how 
much water we get in our foods we also need to drink 
water by itself. It might seem that thirst would be 
a good guide to our need of drinking water, yet we 
often would be better for a glass of water even when 
we do not feel thirsty. There is, in fact, no danger of 
our drinking too much pure water. These are good 
habits to form about drinking: 

1. We should make it a firm rule not to drink 
freely of very cold water when we are much 
heated. 

2. We should never drink water in large quantities 
just before violent exercise, as in a game. Ath¬ 
letic coaches do not allow their men to drink 
water during a contest. 

3. It is well to drink a glass of water on rising in 
the morning and on retiring at night, even if we 
do not feel very thirsty. Water may be drunk 
at meal time, but never to wash down food that 
has not been properly chewed. Drink a glass 
or two between meals. 

4. Both because of health and for the sake of good 
manners we should drink slowly, and not gulp 
a glass of water down in a few swallows. 


160 PHYSIOLOGY AND HYGIENE 

Water from wells. —Most of the water we drink 
is either pumped from near-by wells, or drawn from 
the faucet of a city water system. 

Shallow wells, such as most of those on farms and 
in villages, often contain impurities carried in by 
surface drainage. An examination of many farm wells 
made under the direction of experts showed more than 
half of them to contain disease germs dangerous to 
health. 

Epidemics of typhoid fever, cholera and other dis¬ 
eases have frequently been traced to water from wells 
polluted by drainage from some source of infection. 
Water from shallow wells should always be looked 
upon with suspicion, especially if near barns, out¬ 
houses, cesspools or other sources of filth. 

The city water supply. —Towns and cities draw 
their water supply from various sources. Chicago 
pumps its water from intakes several miles out in 
Lake Michigan; New York from reservoirs fed by 
mountain streams; St. Louis from the Mississippi 
River. Many smaller places pump their water from 
deep wells. 

The water from any of these sources is pure enough 
providing it has not received drainage from some 
source of infection. The trouble is that most towns 
and cities pour their sewerage through pipes into the 
rivers or lakes near at hand. Disease germs from this 
sewerage sometimes find their way into the intake 


WATER AS FOOD 


161 


pipes of the city water supply and make the water 
unsafe for drinking. 

To protect against polluted water, many cities filter 
their water supply through great beds of gravel and 
sand. This removes most of the germs and so purifies 
the water. 

Two lessons from other nations. —We may learn 
a valuable lesson concerning our water supply from 
the ancient city of Rome. There are still standing 
sections of a great aqueduct built more than eighteen 
centuries ago to bring pure water from distant hills 
to the great city. The Romans did not know that 
disease comes from microbes, or even that microbes 
exist, but they allowed no impurity to enter their 
supply of drinking water. That is a good rule for us 
to-day. 

The other lesson comes from China. Many of the 
large cities of China take their drinking water directly 
from rivers into which all manner of filth and impurity 
are constantly pouring. Microbes swarm by the mil¬ 
lion in every drop of water used by thousands of people. 
Yet very few take disease from the impure water 
for the simple reason that it is a national habit to boil 
the water before drinking it. The Chinese usually 
steep tea in the boiling water, but the main point is 
that they kill the disease germs by boiling the water. 

Two good rules. — i. Following the example of 
the ancient Romans, each town and city should 


162 PHYSIOLOGY AND HYGIENE 

use every care to keep its water supply clean 
and pure. Every person who owns a well should 
do his best to see that it does not receive drain¬ 
age from surface water nor filth from any source. 

2. Following the example of the Chinese, every one 
who has to drink water which is not known to 
be free from disease germs should boil it before 
drinking it. The following of these two simple 
rules would do much to save needless sickness 
and death. 

Interesting things to do. — I. Make an investiga¬ 
tion to discover where your drinking water 
comes from. If you live where there is a city 
water supply learn what is the source of supply 
—wells, springs, streams or lakes. 

2. Inquire of your father, or some one else who can 
tell you, the difference between a driven well, 
a bored well, and a dug well. If you use water 
from a well, learn to which class your well be¬ 
longs. Which is best? 

3. Investigate wells near at hand, and note whether 
any of them are open around the top so that 
insects, mice or other small animals can get in. 

4. Remember that wells receive their supply of 
water from underground streams or from water 
that has soaked down from the surface. The 
underground slopes are not always in the same 
direction as those on the surface. Do you know 


WATER AS FOOD 


163 

of wells that are near enough to oarnyards, cess¬ 
pools or other dirty places that drainage from 
these sources probably enters the wells? 

Questions to answer. —What is said about the 
amount of water we purchase in certain foods? Why 
do we need so much water in our foods? What pro¬ 
portion of our own bodies consists of water? Explain 
some of the different uses of water in the body. Men¬ 
tion certain of the drier foods to which we add water 
in preparing them for the table. Give rules that we 
should follow in drinking water. Where does most of 
our drinking water come from? What dangers of 
disease may drinking water bring us? Name some of 
the sources of city water supply. What two lessons 
about drinking water are taught us by ancient nations? 

Health Problems 

1. Why does a potato kept over winter shrivel up and grow 
soft? Do you suppose cells in the tissues of our bodies 
suffer in somewhat the same way when they lack sufficient 
water? 

2. Suppose a city has a poor water supply and also poor pav¬ 
ing on its streets, but can afford to improve but one of the 
two, which would it better improve first? Why? 

3. Explain different ways in which cities filter their water 
supply. 

4. If you live in the country study carefully the surroundings 
of your well. If it is a dug well, ask your father if any 
impure drainage could reach it. 


CHAPTER XXII 


WHERE DIGESTION TAKES PLACE 

When our food is once cooked and eaten, we usually 
think no more about it. Yet when we have chewed 
and swallowed the meat, bread, or egg, it is very far 
from being ready for the body to use. It must still 
.go through the process called digestion. Before the 
food is ready for the blood to carry to the tissues, it 
must be dissolved, or made over into liquid form. 
While the process of dissolving is going on, certain 
chemical changes are also taking place. This dis¬ 
solving and changing of the food to prepare it for the 
use of the tissues is what we mean by digestion. 

Where digestion takes place. —Digestion really 
begins in the mouth. Here the food is chewed and 
mixed with the saliva, which partly dissolves and 
starts the process of digestion of the starch parts of 
the foods. 

The digestive tube begins at the back of the mouth, 
passes down through the throat and chest, and finally 
winds back and forth across the lower part of the 
body, called the abdomen. 

Throughout most of its length, the digestive tube 
164 


WHERE DIGESTION TAKES PLACE 


165 



is very narrow, being only one or two inches in diam¬ 
eter. It is long enough, so that if stretched out straight, 
it would reach a dis¬ 
tance of about twenty- 
five feet. 

Different parts of the 
digestive tube are called 
by their own particular 
names. At the back 
part of the mouth comes 
the throat , and imme¬ 
diately below this the 
gullet , which is also 
called by the hard name, 
esophagus . The gullet 
opens into the stom¬ 
ach and the stomach in 
turn opens into the in¬ 
testine or bowel. It is 
the part called the in¬ 
testine which lies in 
folds across the ab¬ 
domen. * 


Ve 

Appendix 


The intestine consists The digestive tract 

of two parts, first called 

the small intestine , which comes next after the stomach; 
the small intestine leads into the large intestine . The small 
intestine is much longer and narrower than the large. 








PHYSIOLOGY AND HYGIENE 


166 

The work of the stomach. —The stomach is an 
enlarged part of the digestive tube. It is shaped some¬ 
thing like a pear, and is several inches in diameter. 
Its walls, like those of the remainder of the digestive 
tube, are of muscle, and therefore contract and expand 
to accommodate the amount of food in the stomach. 

One of the chief uses of the stomach is to serve as 
a kind of storage place, or bin, for the food. In the 
time that it takes us to eat a meal, enough food is put 
into the stomach to keep the digestive machinery busy 
for several hours. The stomach expands as the food 
is swallowed into it, having a capacity of several 
pints when very full. 

Once the food has reached the stomach, it finds the 
stomach acting as a kind of churn. The walls contract 
now at this place and now at that, squeezing and push¬ 
ing the food about until it is thoroughly mixed with 
a digestive fluid, called gastric juice , which the stomach 
wall gives out. 

Still another important work of the stomach is to 
kill the bacteria which may be taken in with the food. 
Whenever we eat we are constantly swallowing any 
number of bacteria, most of which are harmless. It 
often happens, however, that living disease germs are 
taken in with the rest. Most of these are killed by the 
acid of the gastric juice, and therefore do us no harm. 

The gastric juice, besides helping dissolve the food, 
brings about certain chemical changes in the proteid, 


WHERE DIGESTION TAKES PLACE 


167 


making a portion of it ready for the blood. When the 
food has been sufficiently churned about, dissolved, 
and changed by the gastric juice, it is ready for the 
intestine. A small muscular gateway, called the 
pylorus , which stands guard between the stomach and 
the small intestine, then opens and allows the liquid 
food to pass on. 

Digestion in the intestine. —The liquid food 
from the stomach finds its way slowly along the folds 
of the small intestine. While in the intestine it is 
mixed with still other digestive fluids, which continue 
the process of dissolving and changing it to make it 
ready for the use of the body. While it is in this stage 
the food, now a thin liquid, is known as chyle. 

Besides the digestive juices which are supplied bv 
the stomach and intestine, two other important fluids 
aid in the digestion of food. These are the bile , which 
comes from the liver, and the pancreatic juice , the' most 
important digestive fluid of all, which comes from a 
small organ called the pancreas. 

From the intestine into the blood. —How the 
food manages to pass from the intestine to the blood¬ 
vessels is not easy at first to see. But once we remem¬ 
ber that certain liquids can easily pass through living 
tissue, as we found in our experiment with the salt 
water, the mystery becomes clear. 

The digestive tube is lined throughout its entire 
length with mucous membrane. This is a sort of skin, 


PHYSIOLOGY AND HYGIENE 


168 


but very much softer, thinner, and more delicate than 
the covering of the body. Mucous membrane has the 
power of absorbing water and any substances that 
may be dissolved in it. 

While the digestion of the liquid food begins in the 
mouth, the most is absorbed, however, from the 
chyle of the intestine. The delicate lining membrane 
of the intestine projects in many folds 
and these are covered by thousands 
of little rootlets called villi which are 
rich in blood and lymph capillaries. 
Each separate villus is busily at work 
drinking in the liquid food which is 
now ready for the blood. The villi 
finally pour into the blood and lymph 
circulations the precious material they 

The villi as they ap- have absorbed, 
pear on the lining of 

the intestine Things that hinder digestion.— 

We have already learned that whatever portion of the 
body is working hardest, demands an extra supply of 
blood. Immediately after we have eaten a meal and 
while the process of digestion is at its height, a large 
amount of blood is needed by the organs of digestion. 

It is easy to see that if we play or work hard imme¬ 
diately after eating, the blood will be required for the 
muscles. If we begin to study hard, the blood will be 
required by the brain. In either case it is drawn away 



WHERE DIGESTION TAKES PLACE 


169 




from the stomach and intestines, and 
they are robbed of their proper share. 

Digestion is then hindered and the 
health suffers. 

Nervousness, fear, excitement, or 
any other strong feeling, also hinder 
the work of the digestion. Exciting 
games or plays carried on imme¬ 
diately after a meal are therefore un¬ 
wise, and should be postponed until 
digestion is well under way. 

Problems to investigate.— 

1. Sometimes when you have 
eaten too much, has your 
stomach felt full and stuffed f 
and perhaps pained you? This 
was the stomach’s way of 
telling you that you had given 
it too much work to do, and 
that it was having a hard 
time of it. 

2. Point out on the picture on 
page 165 all the different parts 
of the digestive tube, and tell 
what work goes on in each 
part. Especially note the appendix, which is at 
the point where the small intestine joins on to 
the large. It is inflammation of the appendix 



A villus of the small 
intestine greatly en¬ 
larged 










170 


PHYSIOLOGY AND HYGIENE 


that causes appendicitis, to cure which the 
surgeon removes the appendix. 

Facts to remember. — i. No matter how much 
food we may eat, it must be digested before the 
body can make use of it. The digestion of just 
the right amount of suitable food brings a com¬ 
fortable, pleasant feeling. For example, it is 
proverbial that one feels good-natured after a 
satisfactory meal. If we feel distress after 
eating we may be sure that something is wrong 
with our digestion. 

2. Digestion begins in the mouth and continues in 
the stomach and the small intestine. The fluids 
or juices that help in digestion are the saliva of 
the mouth, the gastric juice of the stomach, 
certain fluids of the intestine, bile from the 
liver, and especially the pancreatic juice from 
the pancreas. 

3 By far the most, if not all, of the digested food 
is absorbed by the villi of the small intestine. 
The digested proteid and carbohydrates are 
picked up by the blood capillaries and carried 
first to the liver, and the digested fat by the 
lymph capillaries, and carried to the blood. 

Questions to answer. —After the food is chewed 
and swallowed, what must yet be done to it before it 
is ready for the body’s use? What is meant by digest - 


WHERE DIGESTION TAKES PLACE 171 

ing the food? Where does the digestion of food take 
place? Name the different parts of the digestive tube. 
Describe the stomach. Explain how the stomach is 
a storage place for food. Describe how the stomach 
acts in churning the food about during digestion. 
What important work does the stomach do in refer¬ 
ence to disease germs? What digestive fluid is sup¬ 
plied by the mouth? By the stomach? By the liver? 
By the pancreas? What are the villi? What is the 
work of the villi? After the villi have absorbed the 
food where do they carry it? Name several things 
that will hinder digestion. What are several of the 
most important points to be remembered from this 
lesson? 

Health Problems 

1. Imagine you wish to explain to some one who has not read 
about it just how the food we eat becomes living tissue. 
How would you tell the story? 

2. John noticed that after he had eaten pork chops for his 
dinner in the evening he did not sleep well. What was the 
probable condition in his stomach? 

3. The Blank family never seem very happy at meal time. 
Sometimes the children are cross about their food and 
sometimes father or mother scolds. There is hardly a meal 
some one does not shed tears. What effect has this state 
of affairs on digestion? 

4. How can the children of a family make it easier for their 
mothers to plan and prepare the meals? 


CHAPTER XXIII 


THE WORK OF THE TEETH 

The first thing one naturally thinks of concerning his 
teeth is whether they look white and clean, and whether 
they ache or not. There are other questions, however, 
to consider. The teeth have three chief uses, all of 
which are important. These are: 

(1) To grind the food, thus making it ready for the 
stomach. 

(2) To aid in making the sounds in speech. 

(3) To add to the attractiveness of the face. 

The work of the teeth in grinding the food.— 

Perhaps the principal use for which nature intended 
the teeth is to help make the food ready for the stomach. 
Certain it is, anyway, that the animals whose stomachs 
are not able to handle their food in large coarse masses 
have teeth for tearing or grinding it. 

Likewise, each kind of animal has teeth of the form 
best adapted to preparing its particular sort of food. 
Dogs, wolves, and other flesh-eating animals have 
sharp, strong teeth for tearing and rending their prey. 
Cows, horses and many other grass-eating animals have 
broad, flat teeth for grinding their food into a pulp. 
172 


THE WORK OF THE TEETH 


173 


Since man eats many different kinds of food, he has : 
teeth of several different shapes. The four incisors at 
the front with their sharp edges, are just right for bit- » 
ing through a crust of bread, a piece of meat or any 
other substance that needs cutting. The canine and 
the bicuspids at the corner of the jaw, are adapted to 



The permanent teeth as they appear in the upper jaw 


tearing or holding. The molars, farther back in the 
mouth, with their broad, flat surfaces are fitted for 
grinding the food into small bits. Note all of these in 
the above picture, and learn their names and locations. 

Making sure of good mastication. —Mastication, 
or chewing the food, is one of the most important acts 
of digestion. If anything is wrong with the teeth so 
that the food can not be properly ground up into fine 



174 


PHYSIOLOGY AND HYGIENE 


bits before being swallowed, digestion is hindered, and 
some kinds of food are never properly digested. 

One somewhat common defect that interferes with 
proper mastication is the failure of the teeth of the 
upper and the lower jaws to fit together right when the 
jaws are closed. This is called faulty occlusion of the 
teeth, and is sometimes indirectly due to adenoids. A 
more frequent trouble, however, is that from decayed 
teeth, which finally ache and so hinder chewing, or else 
come out and leave a vacant space, which prevents 
proper grinding. 

Many persons who have good teeth, however, do not 
properly masticate their food. Sometimes this is be¬ 
cause they eat in a hurry, and do not take time to chew 
each mouthful. In other cases it is simply a matter 
of habit, or of greedy eating; they have become accus¬ 
tomed to bolting their food in coarse chunks, and so 
this is their manner of eating. 

Boys and girls by the age of twelve or thirteen years 
should have firmly formed the habit of eating slowly, 
quietly and daintily, thoroughly masticating their food 
before swallowing it. There are few ways in which 
good breeding shows more readily than in our manner 
of eating. 

How the teeth help in speech. —One of the best 
ways to understand the part played by the teeth in the 
forming of certain sounds in speaking is to notice some 
one trying to talk who has lost some of his front teeth. 


THE WORK OF THE TEETH 


175 


There are some sounds, such as soft c y ch , /A, and v , 
which can not be correctly spoken without the aid of 
the teeth. 

Very crooked teeth also may interfere with correct 
speech by making it impossible to produce certain 
sounds. Those who are obliged to wear false teeth 
often find that these are enough different from their 
own teeth that they have much trouble in learning 
to speak naturally with a strange set of teeth in the 
mouth. If we would have clear, distinct, beautiful 
speech, we must have good teeth. 

The teeth and good appearance. —One who has 
a set of clean, white, even, sound teeth is pretty sure 
to have an attractive face; for there is no other fea¬ 
ture that has more to do with good appearance than 
the teeth. And it often happens that good looks of 
what might be a pleasing face are spoiled by dirty, 
crooked or decayed teeth. 

The boys and girls who study this book should have 
good teeth. Their teeth should not bear stains, nor 
be discolored, but should be clean and ivory white. 
Their teeth should not be decayed, but if cavities have 
appeared they should be filled by a good dentist. 
Their teeth should seldom ache, if properly cared for. 

The structure of a tooth. —A tooth consists of 
three parts; these are: 

(1) The crown, or the part which can be seen above 
the gum. 


PHYSIOLOGY AND HYGIENE 


176 

(2) The neck, which is a slight narrowing of the 
tooth just at the edge of the gum. 

(3) The root or roots, which fit firmly into holes in 
the jaw bone. 



A section of the tooth as it would appear if split lengthwise 


At the very center of the tooth is a pulp cavity. This 
is a chamber containing blood-vessels and nerves, which 
enter the tooth by a small opening at the tip of each 
root. 

Immediately surrounding the pulp is a substance 
called dentine. This dentine, which is a hard struc¬ 
ture, makes up the greater part of the bulk of the tooth. 








THE WORK OF THE TEETH 


177 


In the root part of the tooth the dentine is covered 
with cement , which is hard and bone-like. In the 
crown, or that part of the tooth which can be seen 
above the gum, the dentine is covered by a thin coat 
of enamel. This is the hardest substance in the body, 
and it serves as an excellent protection to the dentine 
and to the sensitive pulp of the inner tooth. The 
enamel is the glistening white part of the teeth which 
we see, and which we should daily brush. 

Why teeth decay. —Clean teeth seldom decay. 
This is because decay is usually caused by the action 
of bacteria which thrive on food particles left in the 
mouth. The work of the bacteria causes the enamel 
to soften and give away. When the dentine is reached 
the decay is much more rapid, and the protecting shell 
around the sensitive pulp becomes so thin that sudden 
heat or cold in the mouth, or biting on a hard substance 
causes severe pain. 

In time the dentine may crumble away until the 
pulp with its tender nerve roots is inflamed. Then 
the tooth becomes very sore and aches continuously. 
A tooth which has reached this stage usually has to be 
pulled, or else a new crown of some hard substance 
put on the root which remains. 

The action of bacteria upon the enamel is made 
easier by the formation on the teeth of a hard substance 
deposited by the mouth secretions called tartar. The 
deposit of tartar is to be found chiefly between the 


PHYSIOLOGY AND HYGIENE 


178 

lower teeth, and around the base of the teeth at the 
edge of the gum. The white crust of tartar can usually 
be seen on teeth that have not been cleaned by a dentist 
for some time. Even if our teeth do not ache, we 
should have a dentist examine and clean them twice a 
year. 

Reasons for keeping our teeth sound. —It will be 

worth while at this point to recall a lesson we learned in 
Book One: just as clean teeth can only with difficulty 
decay, so also sound teeth do not ache. So if we would 
escape toothache, we must keep our teeth sound. Once 
let a tooth develop a cavity which causes it to ache, and 
there is pain ahead; for the best of dentists can not 
clean and fill such a cavity without causing it to pain 
us. And if we allow it to run on until the tooth must 
come out, the hurt is worse yet; so just to escape un¬ 
necessary pain and suffering it pays to look after our 
teeth. 

But there is an even more important reason why we 
should keep our teeth sound. Decaying teeth give out 
a poison that affects the health of the entire body. 
School physicians have found that many children who 
do not learn easily at school and who are unable to keep 
up with their classes are as bright as anybody and get 
their lessons easily when once their decaying teeth have 
been remedied. The poisons from decayed tooth cavi¬ 
ties affect the brain and nerves so that they can not dc 
their full work. 


THE WORK OF THE TEETH 


179 


A third reason for keeping our teeth sound is that 
it is more or less of a disgrace to allow our teeth to 
decay. Decaying teeth mean rotting food particles, 
unclean mouths, and a poisoned breath. Such teeth 
tell every one who sees them that we lack the pride and 
habits of cleanliness which would prompt us to keep 
our teeth so clean that they would not decay. 

Pyorrhea. —There is another disease of the teeth, 
known as pyorrhea, which is an even more import¬ 
ant cause of bad health of the whole body than is 
the decay we have just described. 

Pyorrhea is the inflammation at the edges of the 
gum and the formation of little pockets of pus be¬ 
tween the gum and the tooth. These pockets burrow 
their way down along the teeth even to the very tip 
of their roots. As a result the soft gum shrinks away 
from the tooth, and its bony socket is dissolved. Hence 
the tooth appears to grow longer and longer. More 
and more of the tooth is exposed and it becomes loos¬ 
er and looser till it may even drop out or must be 
pulled. The pus around these teeth has a very bad 
odor, and makes the breath very offensive. This pus 
mixes with the food which is chewed and so is swal¬ 
lowed. The stomach is thereby poisoned; dyspepsia 
results. More of the pus is absorbed from the gum 
directly into the blood and poisons other organs, espec¬ 
ially the joints and the kidneys. 


l8o PHYSIOLOGY AND HYGIENE 

Pyorrhea is most likely to develop in the mouths of 
those who habitually neglect their teeth, of those who 
brush them unwisely, only scraping their tooth-brushes 
across the teeth at their gum margins, and of those al¬ 
so who have diseased noses and throats. 

How to preserve our teeth. —By following a few 
simple rules nearly every one could keep his teeth sound 
and sweet from childhood to old age. These are the 
rules: 

1. Brush the teeth thoroughly twice each day, using 
a good tooth paste or powder once a day to re¬ 
move the tartar. If they are brushed but once 
a day, this would better be at night. 

2. Run a thread between the edges of the teeth 
each night. A spool of dental floss for this pur¬ 
pose can be bought for a few cents and will last 
for many months. 

3. Eat an abundance of gritty and fibrous foods, 
chewing them well, so that the teeth may be 
given sufficient exercise. 

4. Do not crack nuts with the teeth or bite upon 
very hard substances; for this will chip the 
enamel and so expose the dentine to rapid decay. 

5. Do not change suddenly from very hot to very 
cold substances (or the opposite) in the mouth; 
for this may crack the enamel much as a glass 
is broken by too sudden an application of heat 
or cold. 


THE WORK OF THE TEETH 


181 


6 . Do not wait for an aching tooth to drive you to 
the dentist. An ounce of prevention is worth a 
pound of cure. Pay the dentist for keeping your 
teeth sound instead of for patching them up 
after they have decayed. This will cause you 
less pain and cost you less money. 



When and how our teeth appear. —Because it is 
so important that we should understand about our 
teeth, we will re¬ 
view a few points 
which we learned 
in Book One. 

A full set of 
teeth numbers 
thirty-two, six¬ 
teen in the upper 
jaw and sixteen 
in the lower jaw. 

But the child has 
but twenty. The 
first eight of these 
—the four front 
teeth of each jaw—come in during the first year. 
At two years of age the child should have twenty teeth. 
These twenty, called the milk teeth, are shed between 
the ages of seven and ten. 

The first permanent teeth, the four sixth-year molars, 
should appear during the sixth year. As the twenty 


This picture shows the temporary or milk teeth 
on the right side, and the permanent teeth 
forming in the jaw ready to take their place. 
T emporary T eeth : A and B, incisors; C, canines; 
D and E, bicuspids . Permanent Teeth: F and 
H, incisors; K, canines; L and M, bicuspids; N, 
first (sixth-year) molars. The later molars are 
not shown. 



182 PHYSIOLOGY AND HYGIENE 

milk teeth come out they are followed by permanent 
teeth which take their place. At the age of ten or 
eleven one should therefore have twenty-four of his 
permanent teeth. Four additional molars have come 
in by the age of twelve or thirteen. It is probable 
therefore that the boys and girls who study this book 
will have from twenty-four to twenty-eight teeth. You 
will probably have to wait until you are between seven¬ 
teen and twenty-one years (or possibly even older) 
before the last four molars, or “wisdom teeth,” appear, 
thus giving you your complete count of thirty-two. 

Interesting things to do. — i. By looking in a 
mirror, carefully Count your teeth. Have you 
the proper number for your age? 

2. Make a drawing of a tooth to show its three 
parts, crown, neck and root. Note that some 
teeth have but one root, while others have two 
or three. 

3. Make a drawing of a tooth split from crown to 
root showing (1) the pulp, (2) the dentine, (3) 
the enamel. 

4. If possible, secure from a dentist a number of 
teeth, both sound and decayed, and examine the 
different parts of their structure. 

5. Demonstrate how to brush the teeth properly, 
moving the brush up and down and not across 
the teeth. Also demonstrate how to clean be¬ 
tween the teeth with a piece of thread. 


THE WORK OF THE TEETH 


183 


6. Examine your teeth for tartar; for cavities; for 
deposits of food or for discolored spots. Who 
in the class has the best teeth? The best kept 
teeth? Let the class report on when each paid 
the last visit to the dentist. 

7. By pointing to your own teeth or those of a 
classmate, name each different tooth, telling 
about when it appeared. 

8. Demonstrate the use of the teeth in forming 
certain sounds in speech. 

Questions to answer. —What are three principal 
uses of the teeth? Explain how the teeth of different 
animals are adapted to the kind of food they eat. 
What four different names are used to classify our 
teeth? What different reasons account for poor mas¬ 
tication of food? Explain to just what part of the 
tooth each of these terms applies: crown, neck, root. 
Describe each of the three different layers which go to 
make up the crown of a tooth. Tell what causes teeth 
to decay. What are three important reasons for keep¬ 
ing our teeth sound? Give the rules for preserving the 
teeth. Explain the order in which our teeth appear, 
giving the approximate age at which the different teeth 
come in. 

Health Problems 

1. James brushes teeth pretty well, but does not wash out his 
tooth-brush very well. Give directions for James. 

2. Teeth ofttimes become ulcerated far down on the root and 
require X-ray photographs to reveal the ulceration. How 
might such a condition cause bad health? 


CHAPTER XXIV 


GLANDS AND THEIR WORK 

When you have been sick you may have noticed 
the doctor pressing gently over your body just under¬ 
neath the ribs on the right side, or even thumping 
there a little with his finger and listening to the sound 
made. He was examining your liver to see whether 
it was swollen or not. 

In fact, you can feel the lower edge of your liver 
yourself by pressing your fingers up just under the 
edge of the ribs on your right side. Perhaps the best 
idea of the liver which we can get, however, is to study 
a pig's liver as it comes from the butcher shop ready 
to be cooked for your meal. The liver is the latest 
gland of the body and weighs several pounds. But 
let us first inquire what we mean by glands. 

Gland laboratories. —Glands are the body's spe¬ 
cial factories or laboratories, whose business it is to 
manufacture certain substances required for carrying 
on some particular work. 

Each gland supplies its special kind of fluid or juice, 
which it gives out to do whatever work is required of 
it. There are many different glands in the body, 
some of them large and some small. 

184 


GLANDS AND THEIR WORK 185 

The liver. —The liver is not only the largest, but 
one of the most important glands of the body. It is 
filled with millions of blood capillaries and is always 
crowded full of blood. If you will observe a piece of 
liver while it is being cut, you will notice that the 
blood constantly oozes from it as it does from a piece 
of beef-steak. The liver needs all this blood because 
of the important work it has to do, and also because 
one of its most important duties is to purify the blood. 

The first task of the liver is to act upon the food 
which is carried to it in the blood directly from the 
intestine. We learned in a preceding lesson how the 
villi gather up the liquid food from the intestine. 
This food when first absorbed from the intestine is 
not ready for the use of the body. It must first be 
worked over by the liver laboratories, before it can 
be used to build new tissue or supply bodily energy. 
The blood capillaries of the villi upon leaving the in¬ 
testine unite into larger vessels, and finally deliver 
their load of liquid food to the liver. The liver pro¬ 
ceeds to prepare the food for the use of the tissues. 

So important is this work done by the liver upon 
the food brought to it from the intestine, that if the 
liver should refuse to do its work one would die. 

Besides acting upon the food, the liver does another 
important work. The blood in the large vein which 
runs from the intestine to the liver contains also 
many impurities. While in the liver this venous blood 


PHYSIOLOGY AND HYGIENE 


186 


is worked over, and much of its waste material re¬ 
moved from it. The blood is in this way purified and 
again prepared for the use of the body. The liver is 
very economical in its work, and much of the waste 
material taken from the blood is not thrown away. 
It is made over by the liver into the bile , which, as we 

have already learned, is an 
important fluid used in the 
digestion of food in the 
intestine. 

Alcohol and the liver. 

—It is easy to understand 
from these facts that to be 
well and strong one must 
have a liver that is doing 
wor ^ properly. Ordi- 





narily with right food, ex- 

The lower part of the abdomen, ^ and Qther d hab _ 
showing especially the kidneys, . ’ ( ° 

large blood-vessels and the large its of living, OUr livers never 
intestine trouble us and we would 

hardly know that we have one in our body. Probably 
the greatest enemy of the liver in the world to-day is 
alcohol. Alcohol attacks the liver and injures it in 
many ways so that it is no longer able to do its full 
work in making over the food, nor to remove the waste 
materials from the blood. The drunkard’s liver is 
often found to be so diseased that it is little better 
than no liver at all, and that is, of course, serious. 


GLANDS AND THEIR WORK 


187 

The kidneys. —There are two kidneys, one located 
on each side just above the small of the back. The 
kidneys are bean shaped and are almost the size of the 
palm of the hand. They are very important glands. 
It is their work to remove waste materials from the 
blood. They get rid of the ashes of the food. This 
is so important that diseases of the kidneys which 
hinder them in their work 
are much to be dreaded. 

One kidney disease, called 
Bright’s Disease, causes 
a great many deaths. 

Here again we find that 
alcohol is the greatest 
enemy of the body’s 
glands and their work. 

Physicians tell us that 
drinkers, even of beer, 
are much more liable to 
kidney disease than ab¬ 
stainers. 

The salivary glands. —The saliva which keeps the 
mouth moist and helps to dissolve the food, is supplied 
by three sets of glands on each side of the jaw. The 
saliva is very important in the digestion of starchy 
foods. The bad habit of spitting which some people 
have, is not only disgusting, but it wastes the saliva 
which is needed for digestion. 






188 


PHYSIOLOGY AND HYGIENE 


You may have noticed that when you are frightened 
or nervous or embarrassed, your mouth becomes dry. 
This is because fear or nervousness stops the work of 
the salivary glands. Since the gastric glands of the 
stomach are affected somewhat in the same way, it 
is easy to understand why digestion goes on better 
when one is in a happy state of mind and free from 
nervousness and fear. 

The disease called mumps affects the salivary glands, 
causing them to swell and become very painful. 

Other glands. —There are many other glands in 
the body besides those we have mentioned. The work 
of some of them is not yet understood. Certain glands 
do not have any ducts or tubes leading from them to 
carry the substance they manufacture to other organs. 
They do their work upon the blood as it passes through 
them. The thymus gland is such a gland as this. It is 
located just behind the breast bone; it is large in child¬ 
hood and diminishes in size as one grows older. 

The thyroid gland is located in the neck, just below 
the Adam's apple. The disease called goiter sometimes 
causes this gland to swell, and make the throat larger 
in front. Surgeons sometimes perform an operation 
to remove this trouble. The work of the thyroid gland 
is very necessary to life and health. If the gland is 
too active the patient becomes thin, very nervous, 
the pulse fast and the eyes prominent; if it is too little 
active, the person becomes fat and sluggish in nature. 


GLANDS AND THEIR WORK 189 

Facts to remember. —1. The body has many 
special organs called glands. Each kind of gland 
has its own special work to perform. Just as one 
factory makes shoes, another cloth and a third 
soap, so one kind of gland manufactures saliva, 
another bile, another gastric juice, and so on. 

2. The work of some of the glands is not yet well 
understood, but each gland has some work to 
perform which is necessary for the welfare of 
the body. 

Interesting things to do. —1. Examine the liver 
of a pig or a chicken and find a small, greenish- 
looking bag filled with liquid attached to it. 
This bag contains surplus bile stored up for 
use as needed. 

2. Notice the sudden flow of saliva in your mouth 
when appetizing food is placed before you. The 
saliva enters the sides of the mouth through small 
ducts leading from the glands. The flow may 
sometimes be so strong that a fine stream can 
be seen spurting from the duct. 

3. Observe whether any of the persons you meet 
have swollen thyroid glands; that is, whether 
their throats are enlarged in front. Girls from 
twelve to sixteen years often have slight goiter 
swellings of such kind on their throats. These 
usually disappear without having anything done 
for them. 


190 


PHYSIOLOGY AND HYGIENE 


Questions to answer. —What is the work of the 
glands? Which is the largest of the glands? Where 
is your liver located? What important work is done 
upon the food by the liver? What does the liver do 
in purifying the blood? How does alcohol act upon 
the liver? Where are the kidneys found? What is 
the work done by the kidneys? How does alcohol 
affect the kidneys? Where are the salivary glands 
located? How many salivary glands are there? What 
fluid is supplied by the salivary glands? What dis¬ 
ease sometimes affects the salivary glands? Where is 
the thyroid gland located? What disease sometimes 
attacks the thyroid gland? 

Health Problems 

1. Henry has mumps. What glands are affected? 

2. Imagine you have a friend who does not know about the 
glands of the body. How would you tell him about them 
to make him understand? 

3. Tears are manufactured by glands just over the eyes. 
What different causes will make tears flow? We wash our 
windows every few weeks. How frequently are the eyeballs 
washed ? 

4. Explain the difference between ductless glands and glands 
that have ducts. 

5. Make a list of all the glands of the body which you can 
think of or learn about, giving the work of each. 

6. Why does the throat often feel sore on the outside when 
we have tonsilitis? 


CHAPTER XXV 


THE WONDERFUL BODY 

It seems strange to us now that many of the an¬ 
cients used to look upon the body as vile and not 
worthy respect and care. We of the present day have 
come to see that our bodies are very wonderful crea¬ 
tions. Not only is the body the most marvelous ma¬ 
chine in the world, but it is beautiful as well. 

When painters have wanted something beautiful 
as a subject for their pictures, many of them have 
chosen to paint the human body. When sculptors 
have sought an inspiring subject for their genius to 
work upon they have chiseled in fine marble the 
human form. So we have in our art galleries and 
museums many pictures and sculptures which show 
the grace and beauty of the body. 

Our bodies become still more important when we 
stop to think what they mean to us. We all want 
good minds, but our powers of mind can be no better 
than our brains. We all want skill and endurance, 
but skill and endurance can never excel the strength 
of muscles and nerves. We all want to be well and live 
long, but health and length of life are determined by 
191 


192 


PHYSIOLOGY AND HYGIENE 


the well-being of our bodies. We all want to make a 
good appearance and have people think well of us, 
but our character is judged largely by our bodily car¬ 
riage, poise and self-control. 

The parts of the body. —We have in our various 
lessons studied the different organs and parts of the 



Ready for action. Starting pose for a sprint race 


body, but we have not yet considered the body as a 
whole . Let us think in this lesson of all the organs 
and parts as being united and working together. Let 
us then stop to note how these parts are related to 
each other. 

It is convenient to think of the body as made up of 
three main parts: 






THE WONDERFUL BODY 


193 


(1) The head. 

(2) The limbs. 

(3) The trunk. 

The head. —The head governs all the rest of the 
body. It contains the brain, through which we do 
all our thinking and which governs our acts. In the 
head are located the most of our special senses. Here 
are the organs of sight, hearing, taste and smell. 

Probably the most noticeable part of the head is 
the face. It is the face that gives us our 1 ‘looks,” or 
appearance. Underneath the skin of the face lie hun¬ 
dreds of delicate muscles and sensitive nerves. The 
nerves bear messages from the brain, and every chang¬ 
ing thought causes some change in the muscles of the 
face. This produces our “expression”—our smiles 
and frowns, or our look of glum nature or good cheer. 

The limbs. —By the limbs we mean the arms and 
the legs. It is the possession of these limbs, with the 
Work they can do, which allows man to occupy his 
exalted position on this earth. The shape of his legs 
makes it natural for him to stand upright, and this 
the baby does just as soon as he is strong enough 
without any teaching. It is the hand, however, which 
is the wonderful instrument that distinguishes man 
from all animals. It is the hand which makes it pos¬ 
sible for man to rule the world, to erect our buildings, 
construct or use our machines, write our books, or do 
any one of the many things which men can do better 


194 


PHYSIOLOGY AND HYGIENE 


than animals. No doubt man has risen above the 
animals quite as much because of his hand as his 
brain. 

The trunk. —The trunk consists of a cavity which 
is enclosed by a shell or casing of muscles, bones and 
skin. The cavity of the trunk is divided into two 
chambers, an upper and a lower. The upper chamber 
is called the chest, or thorax , and the lower the belly, 
or abdomen. The two chambers are separated by a 
partition or floor of muscle, the diaphragm. 

In the chest , or upper chamber, are located two sets 
of organs, the heart and the lungs. Besides the many 
blood-vessels which are found in the chest, two prin¬ 
cipal tubes pass through it—the wind-pipe, or trachea; 
and the gullet, or esophagus. 

The trachea leads from the back part of the mouth 
to the lungs, and carries the flood of air in and out 
as we breathe. At the top of the trachea is the “voice 
box,” which can be felt as the Adam’s apple at the 
front of the throat. The voice sounds are made by 
the air passing between two thin strips of membrane, 
called the vocal cords, stretched across the “voice 
box.” Lying just back of the trachea is the gullet, 
which carries the food from the mouth to the stomach. 

The abdomen , or lower and larger chamber of the 
trunk, contains the stomach, intestines, liver, kidneys, 
spleen and pancreas. The organs of the abdomen are 
protected at the back .by the spinal column, the heavy 



THE WONDERFUL BODY 195 

muscles of the back, and the ribs; at the sides by the 
ribs and pelvic, or hip, bones; and in front by the 
walls of muscle and the skin. 

One must remember that besides the organs of the 
abdomen there are many blood-vessels and nerves 
passing through it to the different parts of the body. 


The body can be trained to express joy, gladness, elation or any feeling 

Fat is also freely stored up in this part of the body 
cavity, as you may know if you have ever seen the 
organs removed from the body of a fat pig. In fact, 
this fat is very valuable to protect and support the 
important organs of the abdomen. 

Room for the organs. —The space provided by 
nature for the organs within the trunk is just large 





196 


PHYSIOLOGY AND HYGIENE 


enough for the organs to find room to do their best 
work. It is therefore highly important that we shall 
not crowd this space either by tight clothing, bad 
postures, or any wrong habits of work or play. 

Respecting our bodies. —Do you not think that 
since nature has given us such wonderful bodies we 
should treat them well? Should we not respect them, 
and look upon them as worthy of our best care and 
attention? Should we not train them, and learn to 
control them, so that they may serve us well and per¬ 
fectly carry out our thoughts and plans? 

Some good resolutions to carry out. —1. I will 

not knowingly do anything that will injure my 
body or weaken any of its organs. Especially 
will I not poison its cells with alcohol and 
nicotine. 

2. I will respect my body and keep it pure. I will 
have no habits that will weaken its powers or 
interfere with its skill and endurance. 

3. I will obey the laws of health so far as I know 
them, and do all in my power to keep well and 
strong and free from sickness and disease. 

Questions to answer. —How did many of the 
ancients look upon the body? What reasons have you 
for thinking they were not fair to the body? What are 
the three divisions or parts of the body? What parts 


THE WONDERFUL BODY 


197 


belong to the head? Tell why the hand is so impor¬ 
tant a part of the body. What two parts or cavities 
belong to the trunk? What organs are found in the 
chest? What organs are found in the abdomen? 
What is the name of the partition that separates the 
chest from the abdomen? Tell about the amount of 
space provided in the different chambers for the organs. 
Why do you think we should treat our bodies with 
respect? Give several good resolutions to make con¬ 
cerning our bodies. 

Health Problems 

1. The average length of life is nearly twice as great in this 
country as in India. Can you account for this difference? 

2. It has been said that no machine has ever been invented 
which is as complex and wonderful as the body. What 
reasons can you give for believing this to be true? 

3. Suppose every one would faithfully carry out the three 
good resolutions given on the opposite page, what results 
do you think would follow? 

4. What are some of the principal ways in which people mis¬ 
treat their bodies? 

5. What occupations do you know of which are harmful to 
health? 

6. More clerks and bookkeepers have tuberculosis than farmers 
or carpenters. Why? 

7. Does your schoolroom supply good conditions for health? 
Does your home? 


14 


CHAPTER XXVI 


DISEASE GERMS AND SICKNESS 

Nearly everybody knows nowadays that most of 
our acute illnesses are caused by microbes , or disease 
germs. 

These disease germs are all tiny living plants or 
animals. Each germ is composed of a single cell and 
is so small that it can be seen only through the 
microscope. The one-celled plant microbes are called 
bacteria . The one-celled animal microbes are called 
protozoa . 

Millions of microbes. —As we learned in Book 
One, microbes are to be found all about us. The air 
is full of them. They swarm in water. They live in 
the soil by millions. Every grain of dust carries many 
of them. They attach themselves to our clothing, to 
our food, and even to our bodies. 

Yet all these germs round about us need not worry 
us nor make us afraid. For the fact is, that of the 
three or four thousand kinds which we know only 
about fifty kinds of all the bacteria and protozoa 
can cause disease. Most of the microbes around us 
are not only entirely harmless, but are man’s best 
198 


DISEASE GERMS AND SICKNESS 


199 

friends. Without them neither plants nor animals 
nor man could live. 

How disease germs enter the body.— The mi¬ 
crobes which are harmful to the body are called dis¬ 
ease germs. Disease germs enter the body chiefly in 
three different ways: 

(1) They get in through the skin where there are 
cuts, wounds, or punctures. Germs can not enter 
the body if the skin is unbroken. 

(2) Disease germs are usually taken in through the 
mouth, especially in food and drink. 

(3) We may breathe in certain disease germs through 
the air, and so give them lodgment in the body. 

It is clear from these facts that to protect ourselves 
from germ diseases we have only to keep the germs 
from getting a hold in our bodies. For, no matter 
how many disease germs there may be in the world 
about us, not one of them will do us any harm unless 
it finds a way to enter the body and can there set 
up its growth. 

Preventing disease by destroying the germs.— 

Disease germs being plants and animals, they must 
originally come from other plants and animals of the 
same kind. All disease germs are the offspring of 
other germs of the same species. The first great step 
in the prevention of disease is, therefore, to destroy 
as many disease germs from the body of the sick as 
possible, and not allow them to multiply. 


200 


PHYSIOLOGY AND HYGIENE 


If, for example, we could for a time destroy all the 
germs of tuberculosis coming from the bodies of those 
who have the disease; that is, if we could make every 
consumptive spit into a proper cup which would be 
burned or boiled, there would then be very little 

o 

ft 

Germs causing tet¬ 
anus (lockjaw) 

tuberculosis anywhere in the world. For there is no 
place from which tuberculosis germs can come except 
to be reproduced from the germs already living in the 
bodies of their victims. And without the germs there 
would be no tuberculosis. 




Typhoid germs 



ft) 


& 



Tuberculosis germs 


Pneumonia germs 


If, in the same way we could capture and kill all the 
germs of smallpox, diphtheria, scarlet fever, measles, 
whooping cough, and such diseases as they come 
from the sick, we should then quickly be rid of the 
diseases themselves; for here again there would be 
no disease without the germs. 


DISEASE GERMS AND SICKNESS 


201 


How we take disease. —No germ disease is ever 
caught except by taking into our bodies living germs 
which have recently come from others who have the 
disease. The germs of most contagious diseases, can 
live for but a short time outside the body of the person 
who has the disease. 

Exposure to sunlight kills most germs in a few hours. 
All germs are killed by boiling water, but not by freez¬ 
ing; we may take a disease from using ice containing 
the germs. Many disinfectants, such as carbolic acid, 
formalin, or alcohol, will kill disease germs as soon as 
they touch them. In all of these ways, then, we may 
destroy disease germs and prevent them from giving 
the disease to others. Just as many disease germs as 
possible should be destroyed as they come from the 
bodies of the sick. 

Ways of distributing disease germs. —Many peo¬ 
ple are very careless about giving disease germs to 
others. Yesterday, while on the street-car, I sat beside 
such a person. He was reading his paper when he was 
suddenly seized with a desire to sneeze. He sneezed 
loudly and violently, making so much noise that he 
attracted the attention of the whole car. Instead of 
being ashamed of himself for his bad manners, he 
seemed to think it was a joke and looked about with 
a smile. 

What this man had really done was to spit thousands 
of little droplets of water from his mouth and his nose, 


202 


PHYSIOLOGY AND HYGIENE 


out into the air for other people to breathe! He had 
sprayed the air all around him with moisture that 
carried germs from his own nose and throat. 

Many persons who are themselves well may chance 
to have in their mouth or nose the germs of a cold, of 
pneumonia, or even of tuberculosis. Surely no one 
has the right to cough or sneeze these out into the air 
for other people to breathe. If our friend on the car 



Influenza germs as Influenza germs as found 

they may be seen in in sputum (spit) on the 

the laboratory sidewalk 


must sneeze, why does he not take his handkerchief 
and sneeze into that! If we must cough, shall we not 
cover our mouths, and not distribute germs to other 
people? 

Germs and spitting. —Those who have the dis¬ 
gusting habit of spitting not only offend people of 
good taste, but they also give out whatever germs 
they may happen to have in their mouths. Then 
when the spit has dried and the germs are found 
floating in the air, other people must breathe them. 
Many diseases are spread in this way. 


DISEASE GERMS AND SICKNESS 


203 


Most towns and cities now have laws against spit¬ 
ting in public places; yet there are still those who are 
rude enough to defile the sidewalks, and even the 
floors of public places, by spitting upon them. A 
recent item in a Boston paper tells of five men who 
had just been arrested and fined for spitting on the 
street. The laws against spitting should be rigidly 
enforced, but better still if people will break them¬ 
selves of the filthy habit so that they would be ashamed 
to spit in public! 

How germs cause sickness. —The ways in which 
different disease germs produce sickness in us is a 
most interesting story. As soon as a few of the germs 
have secured lodgment in the blood or in the tissues, 
they immediately begin to grow and reproduce their 
kind. The germs increase very rapidly. Many gen¬ 
erations of them will come to life within the space of 
twenty-four hours. 

Some of the germs, as in the case of diphtheria and 
lockjaw, produce toxins, or poisons, which we can 
easily collect and which would cause the disease if 
injected into the body without the germs. For exam¬ 
ple, enough poison is sometimes produced by the 
growth of small clumps of diphtheria germs on a patch 
the size of a dime in the throat to cause death. The 
tetanus, or lockjaw, germs do not leave the punctured 
wound, but they manufacture a poison which so affects 
the brain and nerves as to cause the muscles to become 


204 PHYSIOLOGY AND HYGIENE 

rigid and set throughout the body. The toxins of the 
most of the disease germs can not be found separate 
from the germs themselves. 

The germs of pneumonia multiply in the lungs, 
and their poison gets into the blood and poisons the 
entire body. The germs of tuberculosis devour by their 
toxins the lungs, or whatever organ they attack. The 
malarial germs destroy the red corpuscles of the blood, 
and so lessen the power of the blood to carry oxygen 
to the tissues. 

But no matter how the disease microbes act to in¬ 
jure us, the damage all comes from the germs securing 
a hold in our bodies and multiplying there. We are 
not to think that the body does not resist the attack 
of hostile germs. The ways in which the body pro¬ 
tects itself against these enemies is so important and 
interesting a story that we will take it up in a later 
lesson. 

Interesting things to do. — i. Inquire of your 
family doctor or a member of your local Board 
of Health what diseases are required by law to 
be quarantined in your city or community. 

2. Learn and report in class what are the laws in 
your state or town against spitting. How well 
are the laws obeyed? 

3. A great deal of the coughing we do is unneces¬ 
sary and could be easily controlled. If one must 


DISEASE GERMS AND SICKNESS 


205 


clear his throat or cough this can be done with 
the mouth closed. Even sneezing can usually 
be checked. Let the class join in a contest to 
see who can for the longest time keep from 
coughing or sneezing in school; also outside of 
school. 

Points to remember. —1. Disease germs can 
come to us only from the bodies of people or 
animals who have the disease. 

2. Disease germs never harm us unless they enter 
our bodies. They may do this through the 
mouth, the nose, or through breaks in the skin. 

3. The way to combat disease is to kill all the 
germs that come from the sick, and not let them 
reach well persons. 

4. It is our duty to see that we do not help spread 
disease germs. We may spread disease by 
coughing, sneezing or spitting, or by careless¬ 
ness about coming in contact with others when 
we are ill. 

Questions to answer. —What two classes of mi¬ 
crobes cause disease? What is the difference between 
bacteria and protozoa? Where are microbes to be 
found? What are the three principal ways in which 
disease germs may enter the body? Explain how dis¬ 
ease can be prevented by destroying the germs. What 
is one way in which we could do away with tubercu- 


206 


PHYSIOLOGY AND HYGIENE 


losis, smallpox, diphtheria, and the like? From what 
source do the germs come that give us different dis¬ 
eases? In what different ways are disease germs dis¬ 
tributed by those who are sick? Explain why people 
should not cough, sneeze or spit in public places. 
Explain how disease germs when once inside our 
bodies act to cause sickness. 

Health Problems 

1. How do disease germs cause sickness—what do they do to 
the body to make us sick? 

2. How do we “catch” germ diseases? 

3. Why is it that certain diseases, as scarlet fever, influenza 
or measles, are much lighter sometimes than other 

4. In the Blank family the baby had scarlet fever, but was 
not very sick, so they did not call the doctor and no one 
outside of the family knew the baby was sick. Mary 
Blank went to school every day. What do you think the 
Blanks should have done when they found the baby had 
scarlet fever? 

5. Suppose a diphtheria quarantine card is posted on your 
neighbor’s house. Tell what persons were responsible for 
its being put up. Who says when it may come down? 

6. What is the usual period of quarantine for scarlet fever? 
Smallpox? Whooping cough? Measles? 


CHAPTER XXVII 


GUARDING AGAINST DISEASE 

Although there may be many disease germs around 
us, it is some satisfaction to know that there are but 
three principal gateways we must guard. As we 
learned in the preceding lesson, we shall be quite safe 
from germs if we can protect against them our mouth, 
our nose, and wounds in the skin. 

Community responsibility for health. —Those 
of us who live in towns or cities can not always make 
sure of the cleanliness of our food and drink. That 
is to say, we can not go back to the farms, to the 
dairies, and to the source of water supply and make, 
sure that the things we eat and drink do not bring us, 
disease germs. 

Town and city dwellers must depend more and 
more on the work done by public boards of health, 
health physicians, market inspectors, etc. Every 
great city, and, in fact, even towns and villages, now 
have their organized health agencies whose business 
it is to look out for the health of the citizens. It is the 
duty of all good citizens to help promote the health 
of their community. 


207 


208 


PHYSIOLOGY AND HYGIENE 


A city’s milk supply. —Those of us who live on 
farms and have our milk come fresh from the dairy 
each morning and night can hardly realize the diffi¬ 
culty in providing a fresh milk supply for a city. 

The milk for city use must, of course, come from 
the farms. It is usually shipped in on special milk 
trains, many of which come from at least a hundred 
miles distance. After reaching the city, the milk has 
to be distributed to milk depots over the city. From 
there it is sent out in wagons and delivered to the 
customers. All this, of course, requires time, and very 
little milk reaches city users within twenty-four hours 
of the time it comes from the cows. 

When the milking has been done with great cleanli¬ 
ness, the fresh milk has at the start about 2,500 bac¬ 
teria for each cubic centimeter (a centimeter is little 
less than four-tenths of an inch; four cubic centimeters 
are one teaspoonful). As milk usually comes from 
the farm, however, it has not less than 30,000 bacteria 
to the cubic centimeter. If the milk is kept very cold 
the bacteria do not increase much within the first day; 
but if it is left luke-warm, there are likely to be about 
5,000,000 bacteria to the cubic centimeter within 
twenty-four hours. 

Germs in milk. —We are not to understand that 
most of these bacteria are disease germs; in fact, very 
few of them are. It is found, however, that milk which 
is full of bacteria is likely to be very bad for the health 


GUARDING AGAINST DISEASE 209 

of children. For this reason, every city now has strict 
regulations concerning its milk supply. It is unlawful 
in some cities to sell milk that contains more than 
100,000 bacteria to each cubic centimeter. 

Milk which has not been kept strictly fresh should 
be pasteurized . This means, as we learned in Book 
One, heating it to a temperature of 140 degrees Fahren¬ 
heit and keeping it at that temperature for twenty 
minutes. This will kill the bacteria of disease (but 
not the harmless ones which sour the milk), and will 
not injure the milk. It is therefore always best to 
pasteurize milk unless we know it is strictly fresh. 
Many prefer to boil the milk. That is an easier and 
surer way to kill the disease germs, but it changes 
the taste of the milk so that it is unpleasant to 
many. 

Disease germs from public drinking cups.— 

Most states now have laws which forbid the use of the 
common drinking cup in public places. Yet it was 
only recently that in a railway station I saw a man 
come to the drinking tank and take a drink from the 
cup. This man wore dirty clothes, his hands were 
filthy with grease and dirt, and his mouth vile with 
tobacco juice. Worse still, there was a great sore on 
one of his lips. After he had put the cup down it was 
soon picked up by a child, who took a drink from it. 
Who knows how many disease germs were left on that 
cup by the man with soiled mouth and diseased lips, 


210 


PHYSIOLOGY AND HYGIENE 


and how many of these gained entrance into the mouth 
of the child! 

We should never under any circumstances use a 
cup from which others have been drinking. Paper 
drinking cups are now commonly supplied in public 
places. Each of us should learn, however, how to 
make a drinking cup quickly and easily out of a clean 
sheet of paper. 

Even the drinking fountain with its stream of flow¬ 
ing water is not safe if the lips are put down over the 
metal. Occasionally those who do not know how to 
drink from the flowing fountain drink with their 
mouths on the metal instead of holding their lips in 
the flowing stream. 

Germs and the soda fountain. —Another source 
of danger from disease germs is the soda fountain. 
The glasses, dishes, and spoons used in these places 
are not always carefully washed. Frequently they 
are only dipped in cold water and carelessly dried on 
cloths that are none too clean. In this way many 
germs left by those who have had disease are left on 
the glasses and spoons, and so are given to other 
people. 

Disease “carriers.” —It has frequently been found 
that persons who have had certain diseases, such as 
typhoid fever, and have themselves perfectly recov¬ 
ered, are still infected with the germs of the disease, 
and for years can give them to other people. Those 


GUARDING AGAINST DISEASE 


211 


who are themselves well, but are still infected by the 
germs of some disease, are called disease ‘'carriers.’’ 

The harm that can be done by disease carriers is 
shown by the case of “Typhoid Mary,” a woman who 
worked as a cook in New York. She for years had not 
had the slightest trace of typhoid herself, yet was 
proved finally to have given the disease to several 
persons, some of whom died. The California State 
Board of Health recently discovered a milkman who, 
though himself well, was a “carrier.” He had given 
typhoid to over two hundred people. In Boston it 
was found that a nurse was a typhoid “carrier” and 
had brought the disease to several of her patients. 

Disease “carriers” may give their germs over to 
others by handling their food or drink, by the use of 
drinking cups, towels, and napkins, or in other ways. 

Besides the “carriers” who distribute disease germs, 
persons who believe themselves perfectly well may 
occasionally have germs of diphtheria, pneumonia, in¬ 
fluenza, or tuberculosis in their mouths. These germs 
when taken by others may result in disease. Because 
of the danger of disease and also for the sake of per¬ 
sonal cleanliness, there are certain rules that every 
person should follow. 

Good rules to follow. —1. Keep your hands clean. 

2. Never put pens, pencils, coins, or any other 
such articles in your mouth. Not only is this 


212 


PHYSIOLOGY AND HYGIENE 


an uncleanly habit, but it is a means of trans¬ 
mitting disease. 



The house rat—always an enemy to man—destroying property and 
carrying disease 

3. Do not share bites from apples or sticks of candy 
and, of course, never trade gum. 

4. Break yourself of the soda fountain habit if you 




GUARDING AGAINST DISEASE 


213 

have it; and if not, be sure not to form it. Not 
only is practically everything served there 
unnecessary when taken between meals, and 
therefore bad for the health, but the use of 
common dishes in most such places means the 
danger of disease. 

5. Never use a common towel. If paper towels 
are not to be had in a public washroom, it is 
far better to use your handkerchief, or even 
allow your hands to dry in the air. 

6. Make it a rule to keep all articles except clean, 
pure, necessary food out of the mouth. This 

• will include your fingers, the corners of your 
books, or any other articles which you have a 
habit of putting into your mouth. 

Rats and mice as disease carriers. —Rats and 
mice are among the worst pests known to man. It is 
estimated that rats and mice destroy each year in the 
United States property valued at over $200,000,000. 
This means that they are constantly destroying as 
much as an army of 200,000 men could earn. 

But an even worse charge can be brought against 
the rat. It is known to carry from one place to an¬ 
other some of the worst diseases that afflict the human 
family. Rats catch a form of the “plague,” and other 
serious diseases, and spread the infection wherever 
they go. The greatest care is used not to let rats from 

15 


214 


PHYSIOLOGY AND HYGIENE 


an ocean-going ship land at the wharf, for fear of the 
diseases they may carry. It has been estimated that 
rats, have caused, through the diseases they have 
carried, more deaths than all the wars of history. 

Rats are one of man’s worst enemies. They should 
have no quarter. Our houses and barns and ware¬ 
houses should be so built as to afford them no place 
to live and no food to eat. Then we should hunt them 
and trap them and poison them and in every way 
seek to rid the world of the danger and destruction 
they bring. Mice are but little less objectionable 
than rats, and should be exterminated. 

Questions to answer. —Why are city dwellers more 
dependent on health officers than those who live in the 
country? Explain how cities and, towns are under¬ 
taking to protect the health of their citizens. Describe 
how a city gets its milk supply. Tell about the germs 
found in milk under differing conditions. When should 
milk be pasteurized? How is milk to be pasteurized? 
Give the case of the man and the little girl drinking 
from the same cup, and the lesson it teaches. What 
should be our rule about drinking from common cups? 
In what way may soda fountains help to spread disease? 
What is meant by disease carriers? Give several il¬ 
lustrations. What is said about disease germs some¬ 
times being found in the mouths of well people? Why 
should this make us all the more careful about using 
common towels, drinking cups and the like? 


CHAPTER XXVIII 

THE BODY’S DEFENSES 

The body is not helpless in the presence of its ene¬ 
mies, the disease germs. Far from it. Nor do we take 
disease every time the germs succeed in finding their 
way into our bodies. On the contrary, as we have 
learned, the germs of different diseases, such as diph¬ 
theria or pneumonia or tuberculosis, are often found 
in the mouths of persons who feel perfectly well. A 
great deal depends on the health of the nose, throat 
and mouth, for the mucous membrane of these cavities 
is almost like the skin, in that a germ can scarcely get 
through a healthy mucous membrane. But if it is dis¬ 
eased by catarrh, bad tonsils or bad teeth, then the 
germs have a much easier time getting into the tissues 
of the body. 

Three modes of defense. —As a matter of fact, 
most disease germs have little chance even if they do 
succeed in getting into the body of a person who is 
naturally well and strong and who takes good care of 
his health. There are three principal ways in which 
the body defends itself against disease germs: 

215 


216 


PHYSIOLOGY AND HYGIENE 


1. The healthy body is always producing germi¬ 
cides , or substances which can kill almost any 
germs. 

2. The white corpuscles attack disease germs and 
destroy them. 

3. The manufacture by the body of antitoxins. 
An antitoxin is the antidote to one, and only 
one, toxin or germ poison. The diphtheria anti¬ 
toxin will protect us against the diphtheria germ, 
and against no other. So with the lockjaw anti¬ 
toxin, etc. 

Germicides in the blood. —Suppose that while 
you are at school to-day one of your friends is cough¬ 
ing and sneezing with an attack of the grippe, and that 
you are ‘‘exposed to the disease.’’ To be exposed 
means that some of the germs have had a good chance 
to find their way into your body. What takes place 
within your body to defeat these germs and protect 
you from having the disease? 

To begin with, our blood at all times contains sub¬ 
stances which act to kill disease germs of every kind. 
These are called germicides. Under ordinary condi¬ 
tions these are able to protect us against the many 
infections to which we are daily exposed. Not depend¬ 
ing on this, however, when the germs of a disease 
start their work, the body begins the manufacture of 
a special germicide to poison these particular germs, 
and no others. These are called antitoxins. It is the 


THE BODY’S DEFENSES 


217 


rapid formation of these antitoxins which in an epi¬ 
demic of scarlet fever, for illustration, prevents many 
persons who catch the disease (and who spread it) 
from feeling sick. For in any epidemic we believe 
there are a great many persons who really have the 
disease, but do not know it, since they feel just about 
as well as ever. It is thanks to protectors like these 
that we seldom have measles or typhoid fever more 
than once. 

As soon as the effect of the grippe germs are felt, 
therefore, a special germicide appears in the blood for the 

destruction of the grippe 
germs. Your body does 
its best to escape its ene- 
, , mies by poisoning them. 

White corpuscles ready to attack 

disease germs The WOrk of the 

white corpuscles. —One of the body’s best defenses 
against the disease germs are the white corpuscles. 
We have already learned how these are always found 
in the blood circulation, and how they even find their 
way out through the walls of the capillaries and wander 
at will in the lymph among the tissues of the body. 

It is the great business of the white corpuscles to 
act as defenders of the body against disease germs. 
They are the soldiers, or the police force, of the body. 
When the disease germs enter the blood or get into 
a wound through the skin, the white corpuscles flock 
in great numbers to the point of attack. 



218 


PHYSIOLOGY AND HYGIENE 


Each white corpuscle seems to select a particular 
disease germ and undertake to wrap itself around the 
germ and destroy it by absorbing or devouring it. 
Sometimes several white corpuscles together may join 
forces to attack a group of germs and surround them 
as a whole. 

The pus, or matter, which comes from sores, is 
made up largely of the white corpuscles which have 
engaged in the fight against disease germs and have 
lost their lives in the struggle. In order to help the 
white corpuscles in their fight against the germs in 
a cut or wound, we use antiseptic washes, which help 
kill the germs and so aid the corpuscles in their battle. 

We may think therefore of a constant battle going 
on within our blood-vessels and tissues between mil¬ 
lions of white corpuscles and the disease germs which 
find their way into our bodies. The corpuscles never 
stop, even when the odds are against them, but like 
valiant soldiers, attack their enemies in deadly combat 
as long as they have life and strength. 

Team work against disease. —In its fight against 
disease the forces of the body show fine team work. 
The germicides and the white corpuscles together 
launch an attack against the enemy. While the 
germicides weaken the germs and reduce their power 
of resistance, the white corpuscles strive to devour 
them completely. 


THE BODY’S DEFENSES 


219 


Whatever disease germs escape the attack of these 
two defenders find that the body has a third line of 
defense. It is soon ready with an antidote of its own 
manufacture to fight whatever poison the germs may 
succeed in producing. By keeping up these three lines 
of defense the body usually triumphs over its disease 
enemies. The germs are all killed or their effects 
removed, and we recover. The body has then won 
its fight. 

How we become immune from disease. —There 
are certain diseases which we are not likely to have 
more than once. For example, a person who has had 
smallpox rarely takes it a second time. 

The same is true of typhoid fever and measles. 
When one is safe from again catching a disease he is 
said to be immune from it. We are immune from 
every disease we are recovering from for a little while 
at least. This immunity may last for life, as in the 
case of typhoid fever, measles, scarlet fever, and 
whooping cough, or for a few years only or for a few 
months, as diphtheria or pneumonia, or but for a few 
days, as in the case of a cold. 

The reason for immunity against a disease we have 
had is not thoroughly understood, but in part, at least, 
is as follows: When the disease germs attack the body 
in the course of the disease a large supply of special 
antitoxin is manufactured, and also the body learns 
how to make it quickly. After the disease has passed, 


220 


PHYSIOLOGY AND HYGIENE 


some of this special germicide still remains in the 
blood, or can be furnished on short notice. As long 
as this is true, we are safe against this particular 
disease. 

High and low resistance to disease. —You prob¬ 
ably know some persons who rarely take diseases 
which are prevalent, and others who are almost cer¬ 
tain to have every disease that comes along. Those 
who do not take diseases easily are said to have high 
disease resistance; those who take diseases easily, low 
disease resistance . This resistance to different dis¬ 
eases varies much with age. The child catches certain 
diseases easily which the grown person does not, and 
grown persons have some diseases which do not attack 
children. 

As a rule, those who are well and strong and who 
have not injured their health by bad habits have a 
higher disease resistance than others of the same 
age who are not in good physical condition. This is 
precisely what we should expect, for only those whose 
bodily vigor is good can depend on a sufficient supply 
of germicides, white corpuscles and antitoxins to de¬ 
feat the germ enemies which attack them. 

Keeping our disease resistance high. —We shall, 

of course, keep out of the way of disease germs when¬ 
ever we can. We will not knowingly expose ourselves 
to any contagious disease. Yet, do the best we may, 


THE BODY’S DEFENSES 


221 



we can not always keep the germs from getting at us. 
Our safety therefore lies in keeping our disease re¬ 
sistance high. It is especially important that nose, 
mouth and throat be in healthy condition, for here is 
where most of the germs enter the body. Here is 
where the first battle is fought and usually won by 
the body. A diseased throat may allow the disease 


Life in the open will insure these boy campers against falling easy prey 
to disease. And the fun itself is worth while 

germ to locate here, grow, and get such a hold that 
the body will have a much harder battle, since many 
more germs will actually enter the body. 

It is encouraging to know that when we are doing 
the best we can for our bodies in other ways we are 
also doing the best to protect it against disease. For 
the secret of high resistance to disease is only this: 




222 PHYSIOLOGY AND HYGIENE 

(1) Keep the body clean and well nourished. 

(2) Supply the lungs and skin with an abundance 
of fresh air. 

(3) Take plenty of good exercise and abundant 
sleep. 

(4) Have no bad habits that injure or weaken the 
organs. 

Things that reduce resistance. —We have often 
heard of people who “worried themselves sick.” 
Doctors tell us that those who most fear taking con¬ 
tagious diseases in epidemics are the ones most likely 
to be attacked, and if attacked are in great danger of 
dying. This is because all fear, worry and bad moods 
interfere with the work of the body in preparing its 
defenses. The body can not get ready its germicides 
and its antitoxins, and marshal its white corpuscle 
army if its vigor is reduced by worry and unhappiness. 

One of the greatest enemies to high resistance to 
disease is alcohol. 

It has been found that drinkers are much less able 
to resist such disease germs as those of pneumonia, 
typhoid fever and the like than those who have never 
used alcohol. This is because alcohol weakens all 
of our body’s means of self-defense. 

Even tobacco has been found to lower resistance to 
disease, and make one fall more easily a victim to the 
attacks of these germs upon his system. 


THE BODY’S DEFENSES 


223 

Interesting points to consider. — 1. Disease 
germs at certain times come in greater numbers 
and are also stronger and more vigorous than 
at other times. With this fact in mind can you 
explain why in some epidemics the disease is 
in mild form, while at another time the same 
disease may be very severe? 

2 . John and William were both exposed to measles 
by playing with a friend who had a mild form 
of the disease. Both John and William took 
the disease. John had a light case, while Wil¬ 
liam nearly died of it. From the facts you have 
learned about how the body defends itself 
against disease germs, see if you can explain 
why William had the disease so much harder 
than John. 

Questions to answer. —Does the body have any 
ways of defending itself against disease germs after 
they have once got a start? Mention three modes of 
defense against disease germs. What is meant by a 
germicide? Are germicides the same for all diseases? 
Tell the story of how the white corpuscles attack dis¬ 
ease germs. What is the pus , or matter, that comes 
from sores? What is meant by antitoxin? How does 
the antitoxin act to defend the body against disease? 
What is meant by becoming immune to a disease? 
What makes us immune to certain diseases? Explain 
the difference between high resistance and low resist- 


224 


PHYSIOLOGY AND HYGIENE 


ance to disease. What causes the difference between 
high resistance and low resistance to disease? How 
may we keep our disease resistance high? Mention 
several things that tend to lower our disease resistance. 
Especially what effect has alcohol or tobacco upon 
disease resistance? 

Health Problems 

1. Two boys, Jack and Tim, went to visit their friend Mack 
who was sick. It turned out that Mack had scarlet fever. 
Jack caught the scarlet fever, but Tim did not. How can 
you explain why one boy caught the disease while the other 
escaped it? 

2. Suppose a rat has been taken prisoner and you are the pros¬ 
ecuting lawyer to try the case. What are the counts you 
will bring up against him? 

3. Imagine some diphtheria germs have got into the blood. 
Describe the various ways in which the body’s defenders 
will attack the intruders. 

4. What disease germs can be carried by a fly? By a mosquito? 

5. Why is it that epidemics of disease often accompany or 
follow a time of famine? 

6. What contagious diseases, which in the past often resulted 
in epidemics which killed thousands, are now well under 
control. 


CHAPTER XXIX 


VACCINATION AND THE PREVENTION OF DISEASE 

Years ago smallpox was a much dreaded disease. 
Every year it claimed its tens of thousands of victims. 
Scarcely anybody escaped. Then Dr. Jenner, an 
English physician, made some very brave experiments 
that have been a great blessing to the world ever since; 
for his courage has freed us from the dread of small¬ 
pox. 

How vaccination was discovered. —Dr. Jenner 
found that milkmaids often contracted from the cows 
a slight disease called cowpox . One of them told him 
that since she had once had cowpox she did not fear 
smallpox. This started Dr. Jenner to thinking, so he 
decided to try an experiment. He secured some of 
the virus , or matter, from the sores of a person who 
had the cowpox. He scratched this virus into the arm 
of a boy; the boy took the cowpox, but was not made 
very sick. 

When the boy had fully recovered the doctor tried 
to give him smallpox by scratching some of the virus 
of this disease into his arm as he had done with the 
cowpox virus. But he could not make the boy take 
225 


226 


PHYSIOLOGY AND HYGIENE 


the smallpox after he had had the cowpox. This 
proved that a person could be vaccinated against 
smallpox. 

Dr. Pasteur, a French physician, tried the same 
kind of an experiment by placing some specially pre¬ 
pared germs of chicken cholera under the skin of well 
chickens. He found that the chickens would have a 
mild form of cholera without becoming very sick, and 
that this would keep them from having the disease 
in its dangerous form later. That is, he could vacci¬ 
nate chickens against cholera. One of Pasteur’s 
greatest discoveries was the cure by vaccination of 
hydrophobia, coming from the bite of a mad dog. 

Vaccination against disease. —Out of such ex¬ 
periments as those of Dr. Jenner and Dr. Pasteur, 
the idea of vaccination against certain diseases arose. 
Vaccination is one of the most important discoveries 
that have ever been made for protecting us against 
disease. Its use has now become quite general, espe¬ 
cially for smallpox, hydrophobia and typhoid fever. 
The result is that smallpox has almost entirely dis¬ 
appeared, and would completely disappear if every 
person would be vaccinated; while typhoid fever was 
scarcely met with during the last great war. 

After learning how germicides work in the blood 
to combat the germs of disease, we can easily imagine 
how vaccination can protect us. 'The person who is 
vaccinated is really given a mild form of a very similar 


THE PREVENTION OF DISEASE 


227 


disease, usually not severe enough to make him even 
feel sick. As soon as the disease begins, the body at 
once starts manufacturing the germicide required to 
destroy the germs, and can do it quickly in the future. 
Hence we do not again take the disease; we are 
immune. We call this immunity “active immunity,” 
since the person manufactures his own antitoxin. 

Why we should be vaccinated against small¬ 
pox. —Vaccination against smallpox is now com¬ 
pulsory in our army and navy. It is also required in 
many states before pupils can be admitted into the 
schools. In the recent European war the German 
army had almost no cases of smallpox, while the 
French army was troubled by this disease. The dif¬ 
ference was caused by the fact that vaccination has 
been compulsory in Germany for many years and the 
German soldiers were all vaccinated, while the French 
were not. 

There are some who still oppose, or are careless 
about, vaccination against smallpox. Such persons 
should remember that without vaccination, smallpox 
would to-day be a dreadful scourge, as it was in former 
times. Without vaccination smallpox would probably 
kill as many persons as tuberculosis does now. We 
should remember that vaccination prevents smallpox, 
and that if all would be vaccinated smallpox would 
entirely be done away with in a short time. 

Being vaccinated is a very simple matter. It re- 


228 


PHYSIOLOGY AND HYGIENE 


quires no more pain than the scratch of a pin. Very 
few serious results ever follow from proper vaccina¬ 
tion. The person who is vaccinated not only protects 
himself, but makes certain that he will not give the 
smallpox to others. 

Where smallpox vaccine comes from. —Probably 

all the boys and girls who read this book have either 
been vaccinated or soon will be. It will therefore be 
interesting to know where the vaccine , or virus, that 
is put into your arm comes from. 

Smallpox vaccine is obtained by planting the germs 
of cowpox in the skin of a young and healthy calf. 
This gives the calf the cowpox, and in a few days the 
skin is covered with blisters, which contain lymph 
filled with the germs of cowpox. Cowpox seems to be 
but an animal form of smallpox. 

The lymph is taken from the skin of the calf and 
put into little glass tubes which are carefully sealed 
so that the air and dust can not get at them. The 
vaccine is then ready to plant in the arm of the person 
to be vaccinated; it will give him mild cowpox, and 
this will make him immune to smallpox. 

Vaccination protects against typhoid fever.— 

Vaccination is also coming into common use to prevent 
typhoid. In the war between the United States and 
Spain in 1898, many more soldiers were killed by 
typhoid fever than were lost in battle. In the great 


THE PREVENTION OF DISEASE 229 

European war typhoid fever was almost unknown in 
the armies of France, Great Britain, and the United 
States. These nations vaccinate every soldier against 
typhoid. 

As in the case of smallpox vaccination, vaccination 
against typhoid produces a mild illness, but not enough 
to cause serious trouble. The person who has been 
vaccinated with dead typhoid virus is immune to this 
disease for several years, but the effects of the vaccina¬ 
tion do not last as long as the vaccination against 
smallpox. 

Vaccination against other diseases. —The use of 

vaccination is extending to still other diseases. It has 
been used with success for the plague and for cholera; 
some think they have discovered vaccines against 
grippe, but we are not yet sure. 

Prevention of diphtheria. —Until recently diph¬ 
theria has been counted one of our most dangerous 
and dreadful diseases. An antitoxin has, however, 
been discovered for diphtheria. 

Diphtheria antitoxin is obtained by planting diph¬ 
theria germs in the blood of a horse and allowing the 
horse to develop a mild case of diphtheria. More and 
more germs are injected into the horse’s veins from 
day to day until its blood becomes very strong in 
diphtheria antitoxin. The blood is then drawn from 
the veins of the horse and prepared for use in the 

human body. This horse’s blood contains just what 

16 


230 


PHYSIOLOGY AND HYGIENE 


your blood would contain if you had diphtheria and 
got well, only a great deal more of it. The horse has 
done the work of forming antitoxin for you. 

If given early in a case of diphtheria, the antitoxin 
will always make the disease lighter and help in its 
cure. Well persons who are exposed to diphtheria 
should also take the antitoxin treatment, as it will in 
most cases prevent them from taking the disease. 

Immunity from diphtheria by taking the antitoxin 
treatment lasts only for a few weeks, and not for sev¬ 
eral years, as is the case with smallpox or typhoid 
vaccination. Similar antitoxins are used in the pre¬ 
vention and cure of lockjaw and meningitis. We call 
this immunity “passive immunity/ 1 since the horse 
makes the antitoxin for us, not we for ourselves. 

In order that you may understand clearly the dif¬ 
ference between a serum and a vaccine, note this: 
A vaccine consists of the disease germs themselves; 
living, as in the case of cowpox and hydrophobia, or 
dead, as in the case of typhoid fever. These germs 
when injected stimulate us to make our own antitoxin. 
A serum is from the blood of a horse or patient who 
has had the disease. A serum contains no germs or 
toxins, but does provide a great deal of antitoxin “ready 
made” for us. 

Interesting things to do. — i. Let each member 
of the class inquire at home and be able to give 
the following information: 


THE PREVENTION OF DISEASE 


231 


(1) The date of his first vaccination for smallpox, 
and whether it “took.” 

(2) How many vaccinations all told he has had. 

2. Compare the vaccination scar on your arm with 
any other scar to be found on your skin. Is the 
scar from vaccination deeper and unlike other 
scars? 

3. Let the members of the class report whether 
they have ever had diphtheria. How many of 
the class have taken diphtheria antitoxin? Make 
the same report for typhoid. 

4. If you do not already know from experience, 
inquire of your parents or the doctor how the 
doctor vaccinates (1) for smallpox, (2) for 
typhoid. Now, imagine that you are a doctor 
and show on a classmate how you would vac¬ 
cinate him for each of the two. 

Questions to answer. —Why was smallpox dreaded 
so much more many years ago than it is now? Tell 
the story of how Dr. Jenner discovered vaccination 
against smallpox. Tell about Dr. Pasteups experi¬ 
ments in vaccinating chickens. How does vaccination 
keep us from taking a disease? How has vaccination 
shown its value in the case of soldiers? Tell how the 
virus for smallpox vaccination is obtained. What 
other diseases besides smallpox is vaccination used for? 
Tell how diphtheria antitoxin is secured. 


/ 


CHAPTER XXX 

COMMUNITY COOPERATION AND HEALTH 

Every good citizen, whether young or old, feels some 
responsibility for his neighbor's health, happiness and 
well-being. What each one does and how he lives 
affects, in some measure, all the rest. Carelessness in 
one’s own home or school or community may endanger 
the health or life of many others. 

Responsibility for others. —For example, a serious 
epidemic of typhoid which caused the death of many 
persons was traced to the carelessness of one family 
where there was a case of this disease. Instead of 
treating the refuse from the body of the patient with 
carbolic acid or some other germicide before disposing 
of it, the refuse was emptied out on the grounds some 
distance away from the house. From here it was 
washed into a small stream and then the germs were 
carried on into a river from which a city drew its water 
supply. The result was that two hundred persons 
were sick and more than twenty lost their lives, all 
because the members of one family in the community 
were either ignorant or careless. 

232 


COMMUNITY COOPERATION AND HEALTH 233 

The home and community health. —Our homes 
are, of course, first of all for the members of our own 
families. We want them clean, pleasant and healthful 
for their occupants. But the home has also another 
responsibility. Each home is a part of a community, 
and should do its share to make the community a 
desirable place to live. 

The home located in the open country, with no 
other homes near by, has a responsibility for the health 
of others differing from that of the town or city home. 
This country home may sell milk, butter, fruit, or other 
foods. If so, then the farmer should keep the food 
clean and free from disease germs. This will require 
clean barns, good water, and high standards of clean¬ 
liness in the handling of all food products. No filth 
or unclean drainage should be allowed to be carried 
into streams from which others may secure drinking 
water. The home and its surroundings should be kept 
neat, clean and attractive, so that they may be a source 
of pride to the owners and an example to others in the 
neighborhood. Nothing about the home should be 
offensive to neighbors or endanger the health of any 
person in the community. 

The town or city home. —Those who have their 
homes in town or city communities have a still greater 
responsibility for the common welfare. This is because 
so many people are affected by anything that endan¬ 
gers public health. In some cities as many as two or 


PHYSIOLOGY AND HYGIENE 


234 

three thousand people live in a single tenement block. 
These families use common stairways, elevators and 
halls; they wash their clothes in the same laundry 
tubs; they depend on the same fire-escapes in case of 
fire; they are passing and repassing one another at 
close range every day of the year. 

This all means that sickness, disease, uncleanliness 
Or anything else that endangers one home will in some 
degree endanger many other homes as well. A con¬ 
tagious disease not properly cared for in one family 
may quickly spread until it has found victims in many 
families. Impurities, evil smells or poor housekeeping 
in one apartment make it unpleasant for other apart¬ 
ments near by. 

All cities have a law forbidding any one to obstruct 
a fire-escape by placing upon it anything that might 
hinder its use in case of fire. Yet many lives are lost 
in cities every year because some one had placed fur¬ 
niture, bedding, boxes or the like on a fire-escape. It 
is well known that dust is dangerous to health, yet 
there are those living in crowded districts who will beat 
their rugs near other people’s open windows or doors,! 
or shake their rugs out of their own windows, and thus 
allow the germ-laden dust to enter their neighbors’ 
houses. There are those who will throw garbage or 
refuse out into the alley or back yard thereby attract¬ 
ing flies and germs to annoy others or endanger their 
health. 



COMMUNITY COOPERATION AND HEALTH 235 

Do you not think that each of us, whether he lives 
in city or country, should be a good enough citizen to 
make sure that nothing in or about his home shall annoy 
or endanger others? 

The school and community health. —School is 
not only a place in which to train our minds, but also 
a place in which to train our bodies and make sure of 
health and strength. Every member of the school 
who is a good citizen will desire to do all he can to make 
the school free from danger to the health of every pupil. 
Here are some of the requirements of good citizenship 
in the school. 

1. Every good citizen in the school is clean. This 
means having a clean body, clean clothes, clean 
speech, clean breath. 

2. Good school citizens do not knowingly endanger 
others by coming to school when they have a 
contagious disease; by coughing or sneezing 
near others; or, when they have a sore throat, 
by putting anything in their mouths which others 
may touch. 

3. Good school citizens help to keep the school- 
house and premises clean. They do not need¬ 
lessly carry in dirt or dust, nor litter the school 
room, toilets or yard with paper or other rub¬ 
bish. 

4. Every good citizen in the school will cheerfully 
do his part toward helping keep the room well 


236 


PHYSIOLOGY AND HYGIENE 


ventilated, the temperature right, the light prop¬ 
erly adjusted, or take any other responsibility 
given him by the teacher for the common wel¬ 
fare. 

5. No good school citizen will drink from a common 
cup when he has a sore throat, or a sore on the 
mouth or lips. Nor will he use a common towel 
or common wash basin when he has diseased 
eyes or skin. 

6. No good school citizen will come to school after 
having had an infectious disease, or come from 
a home where others have an infectious disease, 
without first making sure by consulting a doctor 
that he will not give the disease to others. 

7. All good school citizens will submit to vaccina¬ 
tion, dental or other health examination, or any 
other measures planned by the public authori¬ 
ties for public health and safety. 

The community and public health. —The com¬ 
munity itself has many responsibilities for public 
health. All towns and cities and even most rural com¬ 
munities, have their boards of health, their public 
health physicians and nurses, their food inspectors, and 
other agencies to safeguard the health of their citizens. 
Some of the chief points at which the community, 
working through its health officers or through civic 
organizations, can provide for public health are: 


COMMUNITY COOPERATION AND HEALTH 237 

1. The inspection of the conditions under which 
food is produced and sold. This will include 
the inspection of dairies, bakeries, ice-cream fac¬ 
tories, and other places where food is prepared 
or marketed. 

2. Making sure of a good water supply free from 
all danger of pollution from drainage which 
might bring to it disease germs or other impuri¬ 
ties. 

3. Clean streets and alleys, free from unnecessary 
dust, rubbish or refuse of any kind. All citizens, 
including boys and girls, should help in keeping 
their towns or cities clean and attractive. 

4. Freedom from unnecessary noises, such as whis¬ 
tles from factories and locomotives, noisy traffic 
on residence streets, automobiles without muf¬ 
flers, or other noises which may be avoided. It 
is known to all physicians that continuous noise 
is very trying, and will finally affect the health. 

5. Freedom from unnecessary dangers, such as 
those from fires, from traffic, automobiles, etc. 
Thousands of persons are killed each year by 
accidents on our streets and roadways. The 
traffic policeman is now an important officer in 
every city, and all good citizens will do their best 
to cooperate with such officers for public safety. 

6 . Providing healthful conditions in factories, shops, 
offices, stores and other public places where peo- 


238 


PHYSIOLOGY AND HYGIENE 


pie work or assemble. This movement has re¬ 
sulted in better ventilated and better lighted 
factories and public buildings. 

7. Providing health officers, hospitals, dispensaries 
and other agencies for protecting the health of 
the people. This also includes the providing of 
public playgrounds, parks and other places 
where the people can go for recreation and 
amusement. 

Community health score card. —The score card 
which follows can be used in judging the health of your 
community. Before scoring any section of the com¬ 
munity, note carefully each of the points, making sure 
that you understand just what it means and how the 
grading or marking should be done. Your teacher can 
help you on this. Different members of the class 
should score without consulting one another, and then 
compare results and discuss the difference in gradings. 


Perfect 


Allow 


HOME 


Drainage good; no pools; basement dry. 

Surroundings clean; no filth, manure, garbage, etc., 

about. 

Ventilation good; windows open for sleeping. 

Rugs; floors painted or oiled, no carpets. 

House well painted, attractive inside and out. 

Barns, dairies, outhouses, clean and well kept. 

Care to protect health; food well selected, doctor and 
dentist consulted when necessary; minor ailments 
looked after. 


10 

10 

20 

10 

10 

20 


20 


100 


t 





















COMMUNITY COOPERATION AND HEALTH 239 


Perfect 


Allow 


SCHOOLHOUSE 


Well ventilated and lighted. 

Regularly cleaned. 

Well dusted; no feather dusters or dry cloths used.. . 

Sweeping compounds; no dry sweeping. 

Blackboards good, erasers and troughs free from chalk 

Adequate space to play; apparatus. 

Pure drinking water; no common cups. 

Clean toilets and cloak rooms. 

Adequate fire protection. 


20 

10 

10 

10 

10 

10 

10 

10 

10 


CHURCH AND SUNDA Y SCHOOL 

Well ventilated. 

Heat right temperature, evenly distributed 

Cleaned regularly. 

Dusting well done, no dry dusting. 

Bare floor or rugs; no carpets nailed down. 
Seats comfortable; no cushions. 


100 


20 

20 

20 

20 

10 

10 


STREETS 

No open sewers. 

No pools or stagnant ponds neglected 

No garbage or rubbish piled up. 

Swept and cleaned regularly. 

Sprinkled and flushed regularly. 

Baskets or cans provided for refuse. ., 
Traffic regulations obeyed. 


100 


20 

10 

10 

20 

10 

10 

20 

100 


The class can easily extend this score card to make 
it apply to moving picture houses (include fire protec¬ 
tion), factories, dairies, markets, or any other interests 
bearing on public health. 





















































240 


PHYSIOLOGY AND HYGIENE 


Questions to answer. —What reasons can you give 
to show that to be a good citizen each person must care 
for the well-being of all? What are several ways in 
which rural homes are responsible for public health? 
What are some of the principal points in which town 
and city homes should seek to promote neighborhood 
health? Give the several requirements of the good 
school citizen with respect to health. Tell the ways 
in which the community may promote the health of its 
citizens. Explain how to use the community health 
score card. 

Health Problems 

1. Some cities have a much lower death rate than others. 
What factors enter into this difference? 

2. Has your community a good record for looking out for the 
health of its citizens? Name some of the enterprises for 
public health which it is carrying on. 

3. Make a list of the ways in which boys and girls can help 
promote the health of their homes and communities. 

4. There are some people who object to being vaccinated, 
saying it is their own affair if they wish to run the risk of 
smallpox. Is this fair to their community? 

5. What conditions, if any, in your community (water, garbage, 
streets, markets) need to be remedied for the protection of 
health? Who are responsible in each case? 


CHAPTER XXXI 


MAKING SURE AGAINST TUBERCULOSIS 

Ordinarily one should think about health rather 
than about disease. He should think about things 
that will make him well and strong and not worry 
about possible sickness. There is one disease, how¬ 
ever, that is so widespread and dreadful that it de¬ 
serves especial attention. This is tuberculosis. 

Tuberculosis causes the death of more people than 
all other infectious diseases put together. About four 
hundred people die every day in the United States 
from tuberculosis. Tuberculosis is caused by a very 
small germ called the tubercle bacillus . 

Facts we should know about tuberculosis.— 

One reason why it is important to study the question 
of tuberculosis is that the disease can often be pre¬ 
vented by very simple measures. Until a few years 
ago it was thought that tuberculosis could not be 
cured. Now we know that even if one has taken the 
disease it can in most cases be cured if taken in time. 

Another mistake that was formerly made about 
tuberculosis was that it was believed to be hereditary; 
that is, people thought that children born of parents 
241 


242 PHYSIOLOGY AND HYGIENE 

who had tuberculosis would be almost certain to 
take the disease. Tuberculosis was therefore thought 
to run in families. But now we know that tuberculosis 
is never inherited; it does not come down as an inheri¬ 
tance from parents to children, but the baby certainly 
has a very easy chance to catch it from its parents 
during the first years of its life. 

How tuberculosis is taken. —Tuberculosis can be 
contracted only by taking into the body the living 
germs from some person who has the disease. We 
may take the germs into our lungs through the air we 
breathe; or into our stomachs through milk or the 
food we eat; or, less frequently, through a break in 
the skin. 

Those who have tuberculosis often are forced to 
cough a great deal. There is great danger that the 
germs from the lungs will be coughed out into the air 
that others must breathe, and so spread the disease. 
Especially is there danger when matter is coughed 
up and spit out. For the sputum (spit) soon dries and 
the germs float in the air. 

A person who is ill with tuberculosis should always 
be supplied with a piece of cloth into which to cough, 
and the cloth should then be burned. Hospitals sup¬ 
ply tuberculosis patients with covered paper cups to 
receive the sputum, which is then destroyed. Those 
who care for one sick with tuberculosis should always 
cleanse their hands thoroughly after handling clothing, 


MAKING SURE AGAINST TUBERCULOSIS 243 

bedding, dishes or any other article used in the sick 
room. 

Tuberculosis from animals. —A number of dif¬ 
ferent animals are subject to tuberculosis. Many 
cows have the disease. Tuberculosis may be taken 
by drinking the milk of tuberculous cows, or from 
eating the meat of an animal that had the disease, 
if the meat has not been well cooked. 

In some states all dairy herds are tested frequently 
for tuberculosis to make sure that infected milk is not 
being sold. Certain cities require milk to be pas¬ 
teurized. Germs in tubercular meat are killed by 
thorough cooking. 

The symptoms of tuberculosis. —Tuberculosis 
can be cured if taken in time. Cases of long standing 
seldom can be completely cured. It is therefore impor¬ 
tant that every one should know the early symptoms 
of the disease and not neglect any trouble that resem¬ 
bles tuberculosis. 

One who has these symptoms should consult his 
doctor; they do not always mean tuberculosis, but it 
is better to be on the safe side: 

(1) A cough that hangs on. 

(2) Night sweats, with fever. 

(3) Loss of weight, or failure to continue growth. 

Curing tuberculosis. —If a person finds that he 
has tuberculosis he should not become discouraged and 



244 PHYSIOLOGY AND HYGIENE 


give up. Thousands of persons with tuberculosis are 
cured every year. 

Only those who live in houses have tuberculosis. 
Those who live out-of-doors are free from it. The 

germ thrives best 
in darkness and 
in stagnant air. 
Sunlight and fresh 
air are its worst 
enemies. Tuber¬ 
culosis attacks 
those whose resist¬ 
ance to disease 
is low. 

These facts sug¬ 
gest the cure for 
tuberculosis. No 
known medicine 
will cure. The pa¬ 
tient must have 
the following: 

(i) Sunlight. 

This Boy Scout is in small danger of tuberculosis (2) Fresh air 
—fresh air, sunlight and freedom from dust make * . 

him safe da Y and 

night. 

(3) Plenty of good, nourishing food, especially 
fatty foods. 

(4) Rest, sleep and quiet. 




MAKING SURE AGAINST TUBERCULOSIS 245 

No doubt the thought has come to you that if these 
four things will cure tuberculosis they will also prevent 
it. And this is true. Possibly none of those who read 
this book may have had the symptoms of tuberculosis; 
it seldom develops in those under fifteen years of age. 
And yet many of you, doubtless, harbor the germ.in 



The Scout patrol is ready for a day’s hike. Fun and health combined 

your bodies. For this reason you should try to grow 
strong and sturdy. It is never a mistake to live in 
sunlight and fresh air, to eat plain nourishing food, 
and to make sure of sufficient rest and sleep. 

Important facts to remember. —1. Tuberculosis 
causes more deaths than flood, famine, fire, 
earthquake, tornado and war combined. One- 
third of all the people who die between the 


17 






246 PHYSIOLOGY AND HYGIENE 

ages of twenty-five and forty-five die from 
tuberculosis. 

2. Tuberculosis is not hereditary; it can always be 
prevented; it can be cured under right treatment 
if taken in time. 

3. Prevention is better than cure. The time to 
prevent is when we are young. Then we will 
not have tuberculosis when we are older. A 
healthy body is the surest preventive against 
tuberculosis. 

4. Tuberculosis attacks especially those who live 
in dark, poorly ventilated rooms. Also those 
who breathe much dust, and cramp their lungs 
by stooping postures. Sunlight and fresh air 
are insurance agains't tuberculosis. 

Questions to answer. —What facts can you give 
showing how important it is that we know how to 
protect ourselves against tuberculosis? How is tuber¬ 
culosis contracted? What measures may be taken to 
make sure that those who have tuberculosis do not 
give the disease to others? What animals are known 
to take tuberculosis? What measures do some states 
take to make sure that tuberculosis is not spread 
through the use of tubercular milk? What are some 
of the symptoms of tuberculosis? Describe the treat¬ 
ment by which tuberculosis is cured. 


CHAPTER XXXII 


PROTECTION AGAINST OTHER COMMON DISEASES 

Some diseases are more likely to attack us when we 
are children, while others trouble us only when we are 
older. Among the diseases more common in childhood 
are, measles, scarlet fever, whooping cough, diphtheria, 
mumps, and chickenpox. These diseases are all con¬ 
tagious; that is, they are contracted from other people 
who have the disease. 

Measles. —More people have measles than any other 
one disease. This is because measles is the most con¬ 
tagious disease of childhood and also because the dis¬ 
ease is spread early, even before the one who has it 
realizes that he is ill. Almost every child who is ex¬ 
posed takes the disease. Nearly every one who will 
have measles has it before the age of fifteen, though 
occasionally the disease attacks adults. 

There are certain well-marked symptoms by which 
measles can usually be known. One feels that he must 
sneeze and blow his nose; his eyes become red and 
watery; there is a cough and a feeling of chilliness- 
A rash comes out on the skin about the fourth day of 
the disease, beginning on the face and neck and soon 
extending to the trunk, arms and legs. 

247 


248 


PHYSIOLOGY AND HYGIENE 


The best way to prevent measles is to keep away 
from those who have the disease. One who has just had 
measles, no matter how light the case, should not 
return to school without the doctor’s directions. This 
is to protect others who may not have had the 
disease. 

The troubles that follow a case of measles are often 
worse than the disease itself. The eyes are weakened, 
the ears often pain and sometimes have gatherings in 
them, the nose and throat are inflamed, and the lungs 
sometimes affected. One who is recovering from 
measles should have the best of care and should be 
particularly cautious about taking cold. 

Scarlet Fever. —Scarlet fever is another germ dis¬ 
ease very common in childhood. The disease is usually 
contracted by coming in contact with some one who 
has it, although the infection is also sometimes carried 
through the milk supply. The most common symp¬ 
toms of scarlet fever are sudden fever, a sore throat, a 
rather severe headache, sickness at the stomach often 
accompanied by vomiting, and a feeling of chilliness. 
About twenty-four hours after these symptoms arise 
a red rash begins to appear, usually first on the neck 
and chest, and gradually spreading down to the arms, 
body and legs. After the disease is pretty well over 
the skin “peels.” 

Scarlet fever, like measles, often brings on other 
troubles. Some of these after-effects are rheumatism, 


PROTECTION AGAINST OTHER DISEASES 249 

heart disease, inflammation of the glands of the neck, 
gatherings in the ear, and tonsilitis. 

While in many communities measles is not quaran¬ 
tined, scarlet fever always is. One who has had scarlet 
fever will usually be a source of infection to others for 
five or six weeks. A physician, however, can tell when 
it is safe to remove the quarantine and allow the patient 
to go back to school. 

Whooping cough. —Most of those who will ever 
have whooping cough have had it before the age of six 
years, hence this disease is not usually very trouble¬ 
some in the school. Whooping cough is extremely 
contagious, and most young children who are exposed 
to it take the disease. 

Whooping cough begins much like an ordinary cold 
or cough, but gradually grows more severe until one 
coughs so violently as to lose the breath quite com¬ 
pletely. At the end of a spasm of coughing the breath 
is drawn in so shortly that the sound made is called a 
“whoop,” which gives the name to the disease. 

One of the worst things about whooping cough is 
that it lasts for about five or six weeks. Occasionally 
it may continue for several months and sometimes 
ends in pneumonia. No one who has a suspicious cold 
or cough, particularly if it is accompanied by a 
* ‘whoop,’’ should go to school without the consent of a 
physician, to make sure that he will not expose 
others. 


250 


PHYSIOLOGY AND HYGIENE 


Diphtheria. —Another disease which commonly 
comes before the age of twelve or fifteen, if at all, is 
diphtheria. Diphtheria may be taken by direct con¬ 
tact from those who have the disease, or it may be con¬ 
tracted from the common use of such articles as pencils, 
handkerchiefs, towels, and the like. It is also thought 
that infected milk may carry the germs. 

The symptoms by which diphtheria is known are a 
rather high fever, headache, a feeling of great discom¬ 
fort, chilliness, loss of appetite, sore throat, and whitish 
patches in the throat. 

Although, as we learned in an earlier lesson, the 
antitoxin treatment greatly reduces the danger from 
this disease, every care should be taken to avoid hav¬ 
ing it, since it is likely to leave us with troubles affect¬ 
ing the eyes, the ears, the throat, or other organs. 
Cases of diphtheria are always quarantined, and the 
quarantine should be very strictly obeyed in order to 
protect others. 

Mumps. —Mumps is a disease which one is most 
likely to take between the ages of five and fifteen. It 
may be called a school disease, since epidemics of it are 
very often found running through schools. The dis¬ 
ease is spread by secretions coming from the nose and 
throat. 

The symptoms of mumps are swelling of the glands 
at the angle of the jaw, a headache, pains in the back 
and sometimes in the legs. Vomiting and fever are 


PROTECTION AGAINST OTHER DISEASES 251 

also common. The glands may swell on one side or 
both sides of the neck. It usually requires two or three 
days for the swelling to reach its height, anti the dis¬ 
ease commonly lasts from a week to ten days. 

Chickenpox. —At one time it was thought that 
chickenpox was a mild form of smallpox, but it is now 
known that this is not the case. 

It is fortunate that chickenpox is usually light and 
harmless, for it is not positively known how the disease 
is carried from one person to another. The symptoms 
by which the chickenpox is known are fever, loss of 
appetite, vomiting, and nose bleed. Several days after 
the fever begins a rash of small water blisters appears 
over the body. 

One who has chickenpox should not go to school 
from the time the earliest symptoms appear until the 
scabs following the eruption on the skin have com¬ 
pletely disappeared. 

Hookworm disease. —There are several chronic dis¬ 
eases which do us much harm, and yet of whose pres¬ 
ence the patient may be quite ignorant. One of them 
is the hookworm disease, especially common in some of 
the southern states. In certain districts nearly every 
person has this disease and yet very few realize that 
they are sick. Persons who have this disease are usually 
undersized, very pale and pasty in looks, are short of 
breath on any exertion and get tired very easily; in 


252 PHYSIOLOGY AND HYGIENE 

fact, they are always tired and so are called lazy. But 
they are not really lazy; they are sick and do not 
realize it.* 

The cause of hookworm disease is a little white worm 
named from its shape, the hookworm, which is about 
a quarter of an inch long and looks like a short piece 
of thread. There are sometimes a few, sometimes thou¬ 
sands of these worms in the intestines of one man. 
There they stay, causing by their tiny bites little bleed¬ 
ing points on the wall of the bowel. If we examine 
with a microscope the bowel movements of these 
patients we find in it a lot of the tiny eggs of these 
worms. 

As soon as a person finds he is thus afflicted 
he should at once begin treatment. If he does, he 
soon will be rid of the worms and then will get well. 
It is these tiny eggs which spread the disease, for after 
they are expelled from the body they hatch in the warm 
ground, setting free very tiny worms too small to be 
seen without a microscope. These eggs may cling to 
the feet of some barefooted child, burrow their way 
through the skin, causing as they do so, “ground itch.” 
They are then carried by the blood to the lungs where 
they make their way into the air spaces, are coughed 
up with the sputum, then swallowed and develop in 
the bowel into the adult worm. You can see that one 
of the best ways to avoid this disease is to wear shoes 
and to keep the body, especially the hands, clean. 


PROTECTION AGAINST OTHER DISEASES 253 

Interesting things to do. —1. Let each member 
of the class consult his parents and then make a 
list of all the infectious diseases he has had. In 
each case tell (1) at what age, (2) the source of 
exposure if known, (3) whether very sick, (4) 
how long the sickness lasted. 

2. After investigating at home let each member of 
the class report whether there were any other 
troubles following an attack of disease, such as 
discharging ears, weak eyes, or rheumatism. 

3. By inquiring of a physician or a member of a 
local board of health learn all the different dis¬ 
eases which are subject to quarantine in your 
community. 

Questions to answer. —What are the diseases most 
commonly affecting children? How is measles con¬ 
tracted? What are the symptoms? What troubles 
sometimes follow a case of measles? At what age is 
scarlet fever most common? How may one take the 
disease? What are the symptoms? What are some of 
the bad effects? At what age is one most likely to have 
whooping cough? How may whooping cough be 
detected? What are the symptoms of diphtheria? 
What treatment greatly reduces the danger from diph¬ 
theria? How may diphtheria be conveyed? Describe 
a case of mumps. A case of chickenpox. Describe 
the hookworm disease. How is it taken? 


CHAPTER XXXIII 


THE SENSES 

Some day when the lessons seem long and the tasks 
hard it will do us good to stop and think .of Helen 
Keller. 

From her earliest childhood Helen Keller has never 
been able to hear, nor to see. Her lack of sight kept 
her from coming to know the world of objects about 
her as we know them. Her lack of hearing kept her 
from learning to talk, for we first learn our speech by 
imitating the speech of others. 

So when Helen had reached the age at which you 
began school, her mind was still very much a blank. 
Not only was she unable to talk, but she did not even 
know what speech meant. She did not know that 
things have names, and had not learned the name of 
a single object about her. She had no way of asking 
for what she wanted, or of making her needs known. 
She knew nothing whatever of the blue of the sky, the 
gold of the sunset, or the color of birds and flowers. She 
had never heard the sound of a voice, the song of a 
bird, nor the tones of music. 

254 


THE SENSES 


255 


How Helen Keller learned. —In spite of being 
blind and deaf Helen Keller is to-day a finely educated 
young woman. She has graduated from college, knows 
several languages, and has written interesting books. In 
her book, 77 ^ Story of My Life , which is very interesting 
to read, Miss Keller tells how she first came to learn. 

Her teacher began by spell¬ 
ing words out with the tip of 
her finger on the palm of 
Helen’s hand. In that way 
Helen learned the names of 
the common objects, such as 
her doll, kitten, chairs, and 
the names of people. Then 
she learned to read with her 
finger-tips by means of the 
raised letters used for the The eye, showing its muscles of 

blind. Finally by holding the control, the tear gland, and the 

bony socket in which it rests 

tips of her fingers on the lips 

and throat of any one speaking, she was able to read 
their words directly from their lips. 

Of course all this was very difficult. And those of 
us who can hear and see ought not to call any task 
hard when we remember that Helen Keller learned all 
the many things she knows without the use of either 
eyes or ears. We ought to be very thankful if we have 
perfect sensory organs, and ought to learn how to 
protect them. 



PHYSIOLOGY AND HYGIENE 


256 

The sensory organs. —Besides the vital organs, 
such as the heart and lungs, which are absolutely 
necessary to our life, we have another set of organs 
called the senses , or sensory organs. 

The work of one group of the sensory organs is to 
keep us informed of what is 
going on in the world about us. 

The organs of this group are: 

(1) The eye , through which 
we come to know light, 
color, distance, direction, 
shape and size. 

(2) The ear , through which 
we hear sounds, includ¬ 
ing not only the speech 
of those about us, but 
also all the sounds of 
nature. 

(3) Taste and smelL through 

, cavities 

which we come to know 

the different tastes and odors. Through taste 
and smell we are not only able to enjoy our 
food, but also to judge its fitness for our use. 

(4) Warmth and cold , through which we are able 
to judge temperatures, and so protect the 
body from the extremes of heat and cold. 

(5) Pain , through which we are able to know when 
the body is being injured in any way. 



THE SENSES 


257 


(6) Touch , by means of which we are able to know 
when any object is in contact with some part 
of the body. Helen Keller has gained most of 
her education through the sense of touch in 
her finger-tips. 

The work of another group of sensory organs is to 
keep us informed of what is going on in the body 
itself. The senses of this group are: 

(1) The sense of movement and strain in our 
muscles and joints. It is through this sense 
that we are able to control the hand, as in 
writing, or in fact control the body in all its 
movements. 

(2) The sense of hunger and thirst, by which we 
are able to know when the body needs food 
and drink. 

(3) The sense of equilibrium , or balance, which is 
located in the ear, and through which we are 
able to balance the body, walking, standing or 
sitting. 

How the sensory organs work. —Each of the 
senses requires some particular stimulus in order to 
set it going. By stimulus is meant anything that 
causes a sensory organ to act. For example, light is 
the stimulus required by the eye; sound is the stim¬ 
ulus required by the ear. Nor will any amount of 
sound cause the eye to see, nor light cause the ear to 
hear. Each organ must have its own proper stimulus. 


PHYSIOLOGY AND HYGIENE 


258 

The stimulus required by taste must be some sub¬ 
stance that can be dissolved , and then come in fluid 
form to the taste organs located on the tongue. 

The stimulus for smell is a substance that can be 
made to take the form of a gas , like air, and so reach 
the organs of smell in the nose as we breathe it in 
with the air. 

The stimulus for warmth and cold and touch must 
in similar way be fitted to the needs of the sensory 
organ located in the skin. 

Man and his senses. —The lowest forms of life do 
not have as many different senses as we have. The 
rule seems to be that each kind of animal has as many 
senses as it requires to live its own life. For example, 
fish which live in the waters of underground caves do 
not have eyes; for eyes would be useless in the dark. 
Very many of the lower types of animals do not have 
ears; for they do not need to hear. Certain other 
animal forms lack all sense of taste and smell; for 
they do not need them in selecting their food or for 
other purposes. 

Man has many different senses because he needs 
them in order to live successfully and happily. The 
loss or injury of any sensory organ is a great handicap. 
Therefore one of our chief cares should be to under¬ 
stand each of our organs of sense, so that we may 
know and use it wisely and save it from injury. 


THE SENSES 


259 


Care of the sensory organs. —Most of the sensory 
organs do not require special care or attention. The 
sense of taste or smell is seldom injured. The sense 
of warmth and cold and the sense of touch may be 
injured or destroyed when a piece of skin containing 
their end organs is removed, as in the case of a burn 
or other accidents. Usually, however, the skin grows 
back on and no permanent harm is done. 

The two sensory organs most liable to injury are 
the eye and the ear . These organs are so important 
that we will give them special attention in separate 
lessons. 

Problems and experiments. —1. Those who are 
deaf, but have their sight, are now taught to 
read speech from the lips. Have some one speak 
a few words in so low a tone that you can not 
hear, and try to read what is said from his lips. 
Does it seem difficult? 

2. Now try to read from the lips as Helen Keller 
does: Place the tips of the first two fingers on 
the lips of the speaker and your small finger at 
the same time on the front of the voice box. 
Can you recognize any words which are spoken? 
Does this seem harder than to read speech by 
watching the lips? 

3. In spite of Helen Keller’s fine education there 
are some things she can never know as you and 
I know them, simply because she has no sensory 


26 o 


PHYSIOLOGY AND HYGIENE 


organs through which to learn them. Make a 
list of experiences with which you are familiar, 
but which she can never have. 

Questions to answer. —Tell the story of Helen 
Keller. How did Helen Keller first begin to learn the 
names of objects about her? How did Helen Keller 
finally learn to understand the speech of others? How 
does Helen Keller read books? What are the senses 
which give us knowledge of the world about us? What 
are the senses which give us knowledge of the body 
itself? What is the stimulus required by the eye? By 
the ear? By the organs of taste? By the organs of 
smell? Why does man have more sense organs than 
the lower forms of animal life? What are the two 
sense organs most liable to injury? 

Health Problems 

1. We used to speak of ‘‘the five senses,” but we now know 
there are more than five. How many can you count? 

2. Suppose one could feel no pain, would this be an advantage 
or a disadvantage? 

3. What advantage is there in having the nose located directly 
over the mouth? 

4. It has been found that Indians usually can see and hear 
better than white men. Why? 

5. Why is it that when one has been sitting in a dark room 
and the light is suddenly turned on, it seems much brighter 
at first than it does after a, few minutes? 

6. Give illustrations of the same rule at work with other senses. 


CHAPTER XXXIV 


GOOD EYES 

When you have been having your picture taken 
you have probably wondered what the photographer 
was looking at when he covered his head with a dark 
cloth and peered in at the back of the camera. Some 
day ask him to allow you to take a look into the camera, 
when some one is sitting in front of it. You may be 
surprised to see a perfect image, or picture, of the 
person on the glass at the back of the camera. And 
this image is always upside down! • 

The eye like a photographer’s camera. —The 

eye works very much like a camera. In fact, the eye 
is a very small camera that operates itself. The lens 
in a photographer’s camera causes an image of the one 
whose picture is taken to appear on the sensitive plate 
in the camera. A similar lens in your eye causes a 
small image of whatever object you see to form on a 
sensitive part at the back of your eye. We shall better 
understand how the eye works, if we first study its parts. 

The eye is a ball about one inch in diameter. It 
fits in a bony socket of the skull, and rests against a 
pad of fat at the back. 


18 


261 


262 


PHYSIOLOGY AND HYGIENE 


The structure of the eye.—The eye is held in 

place and moved in the socket by six different muscles, 
which are attached to the eyeball. It is well supplied 
with blood by several large blood-vessels which enter 



the ball from the rear. The nerve of sight, called the 
optic nerve , also enters the eye at the back. 

What we see as the white of the eye is a tough, 
leathery cover. This coating is very strong. It con¬ 
tains all the inner parts of the eye and gives the eye 



GOOD EYES 


263 

its shape. In the very front we see a transparent 
window, called the cornea . Stretched a little behind 
this is a curtain, called the iris . Through the center 
of the iris is a hole, called the pupil , through which 
the light passes. The coloring matter, which makes 
our eyes blue, or gray, or black, is spread over the 
front of the iris. 

Inside the eye. —If we could follow the light through 
the pupil, we should find ourselves immediately pass¬ 
ing through a very clear and transparent little body 
about the size of a small bean. This is the lens . The 
space back of the lens is filled with a clear jelly through 
which the light, after passing through the lens, goes 
on to the back part of the chamber. 

The spherical room inside the eye is lined with 
black, to keep out all the light except that which 
comes through the pupil. Over the rear half of the 
eye is spread the retina , which is made by the flatten¬ 
ing out of the optic nerve as it enters the eyeball. In 
the retina are delicate little nerve endings, called rods 
and cones . 

How we see. —When you look at an object, as a 
tree, the rays of light pass through the cornea, on 
through the pupil, then through the lens, and finally 
on to the retina at the back. 

Here a perfect picture, or image, of the tree appears 
on a very sensitive group of the rods and cones. These 
send a message in to the brain, and you see the tree! 


264 


PHYSIOLOGY AND HYGIENE 


Seeing near and far objects. —You have probably 
noticed that when the photographer is about ready to 
take your picture, he turns a screw which moves the 
lens of the camera forward or back as may be required. 
This is to get a good focus . If the focus is not good 
your picture will be blurred and imperfect. If the 
focus is good, every line of your features will come out 
clear and sharp. 

Now the eyeball can not change its shape in order 

to get a proper 
focus. But the lens 
inside has muscles 
which can change 
its shape, and this 
answers just the 
same purpose. 
When we are look¬ 
ing at an object far 
off, the lens becomes flatter. When we are looking 
at an object near by, the lens becomes more round, 
or convex. The reason the lens must change its shape 
for near and far objects is to produce a clear focus, 
or image, on the retina. If anything is wrong with 
the eye so that the focus is not clear, our sight will 
be blurred and indistinct, and we can not see well. 



EYE 


A diagram of the eye showing how the image of 
an object is formed on the sensitive nerve tissue 
at the back of the chamber 


Why people need glasses— A great many people 
have something wrong with the eyeball, or with the 
lens, which makes it impossible to secure a good focus. 




GOOD EYES 


265 


If the eyeball or the lens is too flat, we say they are 
far-sighted . If, on the other hand, the eyeball or the 
lens is too much rounded, or convex, they are near¬ 
sighted, In either case glasses are required to correct 
the trouble. 

Glasses are nothing but lenses to help the eye in 
producing a clear focus on the retina. The eye may 
have other defects than near-sightedness or far-sight¬ 
edness; but 
whatever the 
trouble, it usu¬ 
ally results in 
an imperfect 
focus, and the 
help of glasses 
is required. 

Whe never 
the eye is un¬ 
able to focus 
properly, our sight is imperfect. It is possible for our 
eyes to be working improperly and we not be aware 
of it. There is great danger of seriously injuring the 
eyes if we continue to use them without glasses when 
they need the help which glasses would give. 



Diagram showing how the lens changes its shape for 
near and far objects - . On the right the lens C is flat¬ 
tened by the pull of the ligament D, thus adapting it 
for distant vision. On the left the muscle A is acting, 
thus relaxing the ligament and allowing the lens to 
become more convex, for near vision 


Tests for eye trouble. —There are certain signs by 
which you may know that your eyes need attention: 


266 PHYSIOLOGY AND HYGIENE 

1. Do your eyes smart, feel strained, or pain you 
when you have been using them for some time? 

2. Do you have headaches and feel rather nervous 
when you continuously, use your eyes? 

3. Do the letters on the page you are reading ever 
look blurred? Do they dance about? Do they 
run together as you read? 

4. Do you have trouble to read writing or figures 
on the blackboard or charts when other persons 
at the same distance seem to read the material 
without difficulty? 

If your eyes act in any of these ways, you should 
have them examined by an oculist. He can easily 
tell whether you need glasses or not. It never pays 
to get along without glasses if we really need them; 
for this is sure, sooner or later, to injure our eyes 
permanently. 

Taking care of the eyes. —Our eyes are so neces¬ 
sary, and have so much hard work to do, that we 
should give them the very best of care. The following 
are good rules for the care of the eyes: 

1. Do not read too long at a time. Often an inter¬ 
esting story attracts us and we go on reading 
hour after hour, even when weary eyes tell us 
that we ought to quit. This is not fair to our 
eyes. Give them a rest now and then. 

Do not read in a light that is too dim to see the 
print easily and clearly. On the other hand, 


2. 


GOOD EYES 


267 


do not read in a light that is too bright, such as 
direct sunlight, or when sitting facing an electric 
lamp. In either case the eyes suffer injury. 

3. Do not read, at least for any length of time, on 
a street-car or on a railway journey. The 
jolting about constantly requires changes of 

. focus, and this exhausts the muscles of the eyes. 

4. Do not read or work with the head bent forward, 
or with the eyes too close to the work. Bad 
postures not only overcharge the eyes with 
blood, but cause difficulty in focusing on objects 
that are too close. Keep your head erect and 
your book or your work at a proper distance. 

Curtains protecting the eye. —The eyelids are 
two wonderful little curtains that have the power to 
adjust themselves to protect the eye. Let any danger 
threaten and the curtains quickly close over their 
precious charge. Let the light grow too strong and 
the eyelids close part way or shut entirely, as the 
case may require. 

Winking the lids gently washes the eyeball and 
moistens it with a fluid which comes from small glands 
just above the eyeball. Pain or grief causes a more 
rapid flow of the fluid, and it then runs from our eyes 
(or discharges through a duct into our nose!) as tears. 
Closing the eyelids in winking also gives the eye a 
moment’s rest from work and from the light. 


268 


PHYSIOLOGY AND HYGIENE 


Questions to answer. —Describe what may be 
seen on the plate at the back of a camera when a pic¬ 
ture is being taken. Explain how the eye works like 
a camera. How is the eye held in place? How many 
muscles move the eye? Where does the nerve of sight 
enter the eye? Describe the cornea. The iris. The 
pupil. What is the work of the lens? Explain how 
we see. What takes place in the eye when we look 
from near to far objects? Why do some people need 
glasses? What are the signs by which we may know 
whether our eyes need attention? Give several rules 
for the care of the eyes. Explain how the eyes are 
protected by the lids and washed by the tears. 

Health Problems 

1. If you live in a city, watch one hundred people pass by you 
on the street. How many of them wear glasses? 

2. Suppose glasses had never been invented, what difference 
would it have made to human life? 

3. If you get a chance, take a camera to pieces and see how 
it works. Then compare the eye to a camera. What im¬ 
portant points of difference are there? 

4. What are the most frequent causes of blindness? 

5. What are the different methods that have been invented 
to enable the blind to read? 

6. What causes “cross-eye”? How does the surgeon some¬ 
times cure crossed eyes by an operation? 


CHAPTER XXXV 


GOOD EARS 

When we say that a person has large ears, or that 
he froze his ears in a blizzard, we mean of course the 
ear which can be seen. The really important part of 
the ear, however, the part where we actually hear, is 
hidden away in the bones of the skull. 

The three parts of the ear. —The ear is made' up 
• of three distinct parts, each of which has its own par¬ 
ticular work to do in causing us to hear. These parts 
are: 

(1) The outer ear. 

(2) The middle ear. 

(3) The inner ear. 

The outer ear. —The outer ear has two parts: (1) 
the shell attached to the side of the head, which we 
usually call the ear; and (2) the short tube or canal 
which leads into the head. 

The outer shell of cartilage does not have much to 
do with our hearing, although it certainly helps a little 
in gathering waves of sound and turning them into the 
canal of the ear. Another use of the external part of 
the ear is to protect the delicate parts within. The 
269 


270 


PHYSIOLOGY AND HYGIENE 


tube, or canal, part of the outer ear is about one inch 
in length. Across its inner end is stretched a thin 
membrane, called the tympanum , very much like the 
head of a drum. 

The middle ear. —The middle ear is a small cavity 
in the bone of the skull. It is filled with air, which 
finds its way in through a tube that leads from the 
back of the mouth. 

Stretching across the middle ear 
is a string of three tiny bones, 
called the hammer , the anvil , and 
the stirrup . The hammer is at¬ 
tached to the drum membrane at 
the end of the outer tube. The 
stirrup at the inner side of the 
cavity is connected with the inner ear; and the anvil 
connects the other two bones, thus completing the 
chain. 

The inner ear. —The inner ear, like the middle 
ear, is found in a small bony cavity. This chamber is 
filled with lymph. The inner ear is shaped somewhat 
like a snail shell, with a winding canal, called the 
cochlea . In this canal are found thousands of the 
delicate sense organs of the auditory nerve. It is in 
the winding canal of the cochlea that the hearing is 
accomplished. 

Besides the snail shell arrangement which contains 



GOOD EARS 


271 


the cells of the auditory nerve, the inner ear also has 
three tiny canals each of which forms a half circle. 
They are therefore called the semicircular canals. It 
is the work of these canals that enables us to keep our 
balance, or equilibrium. Persons whose semicircular 



A drawing of the right ear 


canals have been destroyed stagger as they walk, and 
lose their sense of direction. 

How we hear. —We have already learned that 
light is the stimulus for the eye, causing us to see. 
In a similar way, sound is the stimulus for the ear, 
enabling us to hear. 





272 PHYSIOLOGY AND HYGIENE 

Whenever a sound is made, waves are caused in the 
air just as waves are produced in water when you drop 
a stone into the pool. The waves of air enter the ear 
through the outer canal; they strike the drum-head 
at the end of the canal and cause this to vibrate. The 
vibration of the membrane moves the chain of bones 
which hang across the middle ear. The last of these 
bones, the stirrup, is in contact with the liquid in the 
inner ear. The movement in the bones is therefore 
carried to the liquid in the inner ear. This affects the 
ends of the auditory nerves, causing them to send the 
message into the brain, and we then hear the sound. 

Care of the ear. —The ear is not likely to be injured 
by over use as is the case with the eye. We may listen 
ever so long to ordinary sounds and the ear does not 
tire. 

Very loud heavy sounds may, however, if too long 
continued, result in injury to the ear. Hardness of 
hearing frequently occurs among those who work in 
factories or other places where harsh, loud, heavy 
noises are continually heard. Loud explosive sounds 
may even drive the air waves against the ear-drum so 
violently as to break it and injure the hearing. 

Gunners on battleships, or those serving heavy guns 
in battle, are required to hold their mouths open when 
the guns are fired. This allows the air from the middle 
ear to escape through the tube which leads into the 
mouth, and so make less strain on the ear-drum. 


GOOD EARS 


273 


Hardness of hearing. —Hardness of hearing may 
be of all degrees, from deafness so slight as to be hardly 
noticed, to deafness so complete that one can not hear 
a gun fired by his ear. Most deafness is caused by 
disease, either in the middle or the inner ear. If the 
nerves of the inner ear are destroyed, one of course 
becomes entirely deaf. 

Most partial deafness is caused by trouble in the 
middle ear. This usually comes from some disease or 
inflammation that causes the joints and membranes of 
the tiny bones of the middle ear so to harden that they 
can not properly do their work. The nerves of the 
inner ear may be ever so perfect, but if the sound 
waves can not be properly carried across to them, we 
of course can not hear well. 

The throat and hearing.— As we have already 
learned, there is a tube that leads directly from the 
back part of the throat into the middle ear. The effects 
of sore throat, adenoids, or colds in the head, often 
extend to the middle ear. Bacteria may find their way 
up the tube, and cause pus, or matter, to form in the 
middle ear. The pressure of the pus sometimes breaks 
through the membrane, and then the ear “runs.” A 
boy of my acquaintance has recently had influenza. 
As he was recovering from the disease his ear began 
to pain him, and in about a day pus began to discharge 
through a hole in the drum-head of his ear. His hearing 
was affected for a time, but as he soon recovered, the 


274 


PHYSIOLOGY AND HYGIENE 


hole in the membrane was repaired by new growth 
and his hearing was again perfect. 

If inflammation is allowed to continue too long in 
the middle ear, the injury to the drum-head may become 
permanent or the membrane be entirely destroyed. 
There is danger also of this inflammation extending 
through to the inner ear and the brain, and causing 
serious trouble. 

To make our hearing safe we must therefore keep 
the mouth and nose in good condition. This means 
to be free from catarrh and the tendency to sore throats. 
It means to get rid of bad tonsils and adenoids if we 
have them. It means to prevent our teeth from 
decaying and to have any cavities immediately taken 
care of. It means the prompt checking of all colds, 
and any troubles that cause the nose to run. 

Care of the outer ear. —No part of the outer ear 
should have rough treatment. Blows on the ear or 
loud explosions near by endanger the drum membrane. 
The yellow wax which forms in the passage is given 
out by glands in the skin. Insects do not like the 
wax and therefore usually keep away from the ear. 

Wax should be removed from the ear by a person 
himself only when it has reached the outer end of the 
tube and come into view. Hard objects, such as 
matches, pencils or toothpicks, should never be put 
into the ear for the removal of the wax. If the wax 
forms in a hard ball, a few drops of warm olive oil may 


GOOD EARS 275 

be put into the ear. This will usually soften the wax 
and allow it to come out. 

Problems and experiments. —1. Do you ever 

have the earache? If so, does it usually come 
when you have been having a cold or sore throat? 

2. How many of the class have had discharging 
ears? Ask your parents about this. Are there 
any who are troubled in this way at present? 

3. How many of the class have had measles, scarlet 
fever, diphtheria, or pneumonia? Did ear 
trouble follow? 

4. Do your ears ever feel full and stopped up? Do 
they have crackling or buzzing noises? If so, 
there is some trouble in the middle ear which 
you should see the doctor about. 

5. An interesting experiment is to have the ears 
of the members of the class tested for sharpness 
of hearing. Your teacher can tell you how this 
should be done by listening (blindfolded) to 
the ticking of a watch as it is held at different 
distances from the ear. 

Questions to answer. —What are the three differ¬ 
ent parts of the ear? Describe each of the two parts 
of the outer ear. How is the outer ear separated from 
the middle ear? Describe the middle ear. What is 
the use of the three small bones that hang across the 
middle ear? What is the use of the tube that leads. 


276 


PHYSIOLOGY AND HYGIENE 


from the middle ear to the mouth? Describe the part 
of the inner ear in which the nerve of hearing ends. 
What work is performed by the semicircular canals of 
the inner ear? Tell how we hear. What care should 
be taken not to injure the ear? In what ways may 
deafness be caused? Explain how sore throat and bad 
tonsils may injure the ear. 

Health Problems 

1. Ask the doctor what are the most common causes of deaf¬ 
ness. He will be glad to tell you. 

2. Sit quietly where it is still and notice whether you can hear 
a buzzing or roaring or crackling in your ears. If you can 
you should have them examined by a doctor. 

3. Explain how a diseased throat may cause trouble in the 
ears. 

4. Lucy likes to hold her nose shut with her fingers, and then 
with her mouth closed blow to “feel her ears puff out.” 
Why should this never be done? Demonstrate how to 
blow the nose without driving air back into the ears. 

5. Why do not insects enter the ear canal and make us trouble 
by hiding there? 

6. Persons who go up on high mountains or to high altitudes 
in an airplane usually have a strange sensation in their ears. 
What is the cause? 

7. Deep sea divers and those who go down into deep mines 
also notice the effect on their ears. Is the cause the same? 


CHAPTER XXXVI 


THE CASE AGAINST ALCOHOL 

In the different chapters of this book and in Book 
One we have been learning that alcohol is an enemy 
to the body. We have found that it always hinders 
and never helps. 

In fact, we have in no place discovered any one say¬ 
ing a good word for alcohol. On the other hand, 
scientists, doctors, business men and other leaders 
unite in taking a stand against it. Let us now sum 
up the case against alcohol and see what our verdict 
should be. 

Alcohol shortens life. —We have read how alcohol 
injures the different organs of the body; we have 
found that it weakens the heart; that it poisons the 
nerves and brain; that it injures the liver and the 
kidneys; and that it lowers resistance to disease. 

Striking proof of these facts is found in a recent 
investigation made by forty-three different insurance 
companies of the United States. It was the purpose 
of the insurance companies to discover whether drink¬ 
ers really die earlier than those who abstain from strong 
drink. Here are the facts they discovered: 

.9 2 77 


278 PHYSIOLOGY AND HYGIENE 

1. Among very moderate drinkers the death rate 
was 18% greater than the average death rate. 

2. Among those who had been drinkers, but who 
had reformed, the death rate was 50% greater 
than the average. 

3. Among steady, moderate drinkers the death 
rate was 86% higher than the average. 

Among all these groups of drinkers, it was found 
that the death rate from kidney diseases, pneumonia, 
and suicide, were higher than for normal people. 

Whether the alcohol is taken in the form of beer, 
wine, or whisky does not seem to matter. The injury 
follows, no matter what the alcoholic drink. And even 
those who have reformed and quit drinking have to 
pay the penalty in a shortened life. 

Laboratory experiments condemn alcohol.— 

Because scientists have desired to be fair to alcohol 
and not to condemn it without good cause, they have 
conducted many experiments in the laboratory to test 
its effect upon the body and the mind. These are 
some of the conclusions they have reached from their 
experiments: 

1. Alcohol decreases the amount of work that one 
can do. This is true whether the work be 
physical labor, or whether it be skilled work 
like that of a compositor in setting type. 

2. Alcohol interferes with mental work. Careful 
experiments have shown that beer or whisky or 


THE CASE AGAINST ALCOHOL 


279 


any other form of alcohol will lower the intellec¬ 
tual power and make one unable to think clearly. 
It interferes with the memory, and makes one 
less accurate in everything from simple addition 
in arithmetic to solving of the hardest problems. 

3. Alcohol reduces the power to withstand extreme 
cold or heat. It has been found that the warm 
glow felt after taking a drink of alcohol comes 
from driving the blood to the skin. But warming 
the skin results in cooling the interior of the 
body. In Polar expeditions all alcohol is abso¬ 
lutely forbidden, since its use is almost sure to 
lead to death from the cold. In hot weather 
the use of alcohol is also condemned, since it 
leads to a feeling of discomfort and makes one 
more liable to sunstrokes. 

4. The drinking of alcohol results in a strong desire 
to continue its use. Alcohol is a habit-forming 
drug. One who has become accustomed to work¬ 
ing under its effects feels that he must contin¬ 
ually have it to spur him on. So the habit 
grows until it makes its victim a slave. 

Alcohol condemned in war time. —Probably the 
most sweeping case ever made against alcohol has been 
made by the nations engaged in the world war which 
began in 1914. Every one of the great nations has 
taken steps either to forbid the use of alcohol or greatly 
restrict its use. 


280 


PHYSIOLOGY AND HYGIENE 



From the National Geographic Magazine, by special permission 

Lieutenant Rene Fonck, one of the most celebrated of the French 
aviators. Lieutenant Fonck reveals the great secret of his marvelous 
success in these words: “One must be in constant training, always fit. 
. . . Alcohol becomes an enemy, even wine. All abuses must be 

avoided” 





THE CASE AGAINST ALCOHOL 


281 


England, France, Russia and Germany all passed 
laws prohibiting the making or selling of certain kinds 
of alcoholic drinks. The United States did away with 
all intoxicants of every sort during the war, and now 
has prohibited their manufacture and sale by con¬ 
stitutional amendment. These are some of the reasons 
why the nations are driving alcohol out during war 
times: 

1. Every nation desires its soldiers to be at their 
best during war. They must have clear brains, 
good endurance, and be as free as possible from 
sickness and disease. But alcohol clouds the 
brain, injures strength and endurance, and low¬ 
ers resistance to disease. 

2. During war each nation must make sure that 
all its citizens at home are doing their best 
through their work to produce food, guns and 
ammunition, clothing and everything else re¬ 
quired in war. But liquor interferes with labor 
and decreases the amount of work that men can 
do. It never fails to lower efficiency, hence it 
must be driven out in time of war. 

3. While war is going on there must be no wastage 
of food materials, since all are needed to feed 
the army and the citizens. But alcoholic drinks 
are made from the grains, fruits and vegetables 
we commonly use for food. Therefore all pro¬ 
duction of alcohol is a wastage of food supplies. 


282 PHYSIOLOGY AND HYGIENE 

4. In time of war every citizen is expected to save 
his money and loan it to the government or pay 
it in taxes in order to provide for the cost of the 
war. But since alcohol is not a good food, and 
since it always injures those who use it, the 
money spent for strong drink is thrown away. 

5. War brings to the people of a nation much suf¬ 
fering, sorrow and distress. But the use of 
alcohol is sure also to result in hardship and 
suffering. It brings unhappiness not only to 
the user but also to his family. 

For these and many other reasons nations and gov¬ 
ernments set themselves against alcohol in time of war 
or other disaster. But if alcohol is not good for a 
nation when it is at war, can it be good for a nation 
when it is at peace! It is unlikely that any of the great 
nations of the present will go back to the free use of 
alcohol which was known before the recent war came 
on. 

The case of business against alcohol. —The em¬ 
ployer and the business man have no tolerance for 
alcohol. And there is no great business concern in 
the United States which does not frown on the use of 
alcohol by its employees. 

Most railway companies will not keep a man in 
their employ who is known to drink. Leading factories 
plainly tell their men that a case of drunkenness will 
result in immediate discharge. In no business or 


THE CASE AGAINST ALCOHOL 283 

occupation will the use of alcohol help one toward pro¬ 
motion and success. In every vocation it will bar the 
way to success, and open wide the road to failure. 

Other facts that condemn alcohol. —1. Before 
national prohibition went into effect it required 
the time and work of about 200,000 men to sell 
the liquor that is drunk in the United States. 
The saloons used 60,000,000 tons of coal a year, 
besides what was used in the manufacture of 
alcoholic drinks. 

2. It is estimated that liquor has been causing the 
death either directly or indirectly of 200 men a 
day in the United States. One out of every 
eight who die in the United States loses his life 
as a direct or indirect result of alcohol. 

3. The cost of liquor for any year in the United 
States has been more than ten times what is 
spent on all churches, and four times what is 
expended on the running of the public schools. 

4. The use of alcohol causes accidents, sickness 
and death. It fills hospitals, poor-houses, in¬ 
sane asylums and prisons. It always corrupts 
the character and breaks down the manhood 
of the user. No good thing ever comes from 
its use. 

The case against alcohol is so strong that our ver¬ 
dict must be guilty !—guilty of everything that is evij 


PHYSIOLOGY AND HYGIENE 


284 

and degrading, with no single good thing that can be 
said in its favor. 

Questions to answer. —How do scientists, doctors 
and business men look upon the use of alcohol? What 
effect has alcohol upon the length of life? Give the 
facts discovered by the investigation made by insur¬ 
ance companies. What effect does the use of alcohol 
have on the amount of work that one can do? How 
does the use of alcohol affect the power to withstand 
extreme heat or cold? How do nations at war look 
upon the use of alcohol? For what reasons do govern¬ 
ments oppose the use of alcohol in war times? What 
other reasons can you give why we should oppose the 
use of alcohol? 

Health Problems 

1. What is the eighteenth amendment? When did it go into 
effect? 

2. What are some of the good results from prohibition? 

3. What is “bootlegging” and what should be done about it? 

4. A man bought whisky from a bootlegger, got drunk and 
killed a stranger whom he met on the street; was the person 
who sold the whisky also guilty of murder? 

5. What is the opinion of most physicians as to the value of 
alcohol as a medicine? 

6. Do you think the eighteenth amendment will be easier to 
enforce when the present younger generation is grown up? 
Why? 


CHAPTER XXXVII 


THE CASE AGAINST TOBACCO 

Tobacco belongs to the same order of plants as the 
potato and the tomato. Yet tobacco contains a power¬ 
ful poison—nicotine—while the potato and tomato are 
valuable foods. 

No one knows when the use of tobacco began, but 
it seems to have been first used by the American 
Indian. In the sixteenth century the Spaniards began 
to cultivate tobacco as an ornamental plant. The 
French first used tobacco in the form of snuff. Soon 
it was widely used in different countries for smoking 
and chewing. 

The governments of most countries first strongly 
opposed the use of tobacco. At one time smokers 
were punished in Russia by having their noses cut off. 

Why people use tobacco. —Those who have learned 
to use tobacco are very much attached to it. Indeed, 
smokers and chewers of tobacco find the habit very 
hard to break. 

Tobacco owes most of its charm to its narcotic 
effects. A narcotic is a drug which, in small doses, 
soothes and quiets the nerves and calms the mind. 

285 


286 


PHYSIOLOGY AND HYGIENE 


In larger doses the narcotic drug may bring on arti¬ 
ficial sleep, make one insensible to pain, and even 
cause death. 

The nicotine of tobacco is a deadly poison. Enough 
nicotine is often found in one cigar to kill two men. 
Only a very small proportion of this poison is taken 
into the blood of the smoker, however, the remainder 
passing off in smoke as the cigar is burned. The 
United States Department of Agriculture has found 
that tobacco smoke contains about thirty per cent, 
of the nicotine originally in the cigar. Some poison 
is constantly being absorbed when one chews or smokes 
tobacco; for the pleasant and quieting effects pro¬ 
duced depend upon the poison absorbed. 

Tobacco and length of life. —The insurance com¬ 
panies have never made as extensive a study of the 
effects of tobacco as they have of alcohol. One insur¬ 
ance company, the New England Mutual, has, however, 
made a study of the effects of tobacco on the length of 
life, and published the results of their investigation. 
The study made by this company covered a period of 
sixty years and related to 180,000 persons insured. 
These are the facts discovered: 

1. Occasional users of tobacco show a death rate 
20% higher than abstainers. 

2. Temperate users of tobacco show a death rate 
42% higher than abstainers. 



THE CASE AGAINST TOBACCO 2«7 

3. Heavier users of tobacco show a death rate 57% 
higher than abstainers. 

From these facts it appears that the use of tobacco 
is almost as injurious to health and length of life as the 
use of alcohol. 

Tobacco injures the body. —Of course, tobacco 
never kills outright those who use it; if it did this its 
use would quickly be forbidden. And it is undoubtedly 
true that a great many people who use tobacco live 
to a good old age; nevertheless we can not get away 
from the fact that tobacco does injure the body. It 
lowers resistance to disease, and leaves its victims less 
able to combat a siege of pneumonia, kidney trouble, 
or some other disorder that may attack them. These 
are some of the ways in which tobacco injures the 
body: 

1. Tobacco affects the heart, and brings on a con¬ 
dition called “tobacco heart.” The heart beats 
faster, the beating is irregular, pains are caused 
in the heart and the breath becomes short. 

No wonder then that captains of football teams and 
athletic coaches all insist that their players let tobacco 
alone. But if tobacco is not good for an athlete, is it 
good for any one? 

2. Surgeons have noticed that tobacco users do 
not rally as well after an operation as non-users. 

One may say that he does not expect to have a 


288 


PHYSIOLOGY AND HYGIENE 


surgical operation, but even if he never does have one 
he needs, for many other purposes, the strength and 
vitality which tobacco is sure to rob him of. 

3. Serious diseases of the nose, throat and ears are 
frequently traced to the use of tobacco. 

Cancer of the throat, which has claimed many 
victims, is blamed by some physicians to the use of 
tobacco. 

4. Smoking sometimes brings “tobacco blindness.'' 
Tobacco smoke also has a tendency to inflame 
the membranes of the eye, making them red 
and painful. 

5. The use of tobacco lowers physical strength and 
endurance. 

Boys who want to become athletes (and what boy 
does not?) will be interested in an investigation made 
in six different colleges and universities by Professor 
F. J. Pack to discover the relation of tobacco to suc¬ 
cess in football. 

Professor Pack found that in these schools there 
were ninety-three smokers and one hundred seventeen 
non-smokers competing for places on the teams. Of 
the ninety-three smokers thirty-one, or thirty-three per 
cent., secured places. Of the one hundred seventeen 
non-smokers, seventy-nine, or sixty-seven per cent., 
secured places. The non-smokers therefore beat the 
smokers out by more than two to one. Professor 
Pack's conclusions are: 



THE CASE AGAINST TOBACCO 289 

(1) Only half as many smokers as non-smokers are 
successful in football competition. 


The man who expects to equal or beat this record can not be 
a user of tobacco while in training 

(2) Smoking is accompanied by a loss of lung 
capacity amounting to about ten per cent. 
Tobacco interferes with mental work. —Tobacco 
interferes with the best mental work as it does with 












290 


PHYSIOLOGY AND HYGIENE 


physical health and strength. It is found in schools 
everywhere that the use of tobacco is accompanied by 
a low average of scholarship. 

For example, among the football men studied by 
Professor Pack, the average of the grades of the non- 
smokers was markedly higher than the grades of the 
smokers. From twelve other colleges comes the report 
that twice as many failures in studies are made by 
smokers as by non-smokers. If tobacco interferes with 
scholarship with men of college age, it will surely 
hinder still more the mental development of the 
younger boys in the grades and high schools. 

Why should boys injure their chance of success by 
dulling their brains with tobacco while getting their 
education! 

Still other counts against tobacco. — i. The 

use of tobacco wastes time. Watch the smoker 
as he stops his work, his reading, or his study 
to light his pipe, his cigarette, or his cigar. 
Attention is always broken into and time lost. 

2. Tobacco costs money. Many persons are spend¬ 
ing money for tobacco which might better go 
into books, travel, education or the savings 
bank. 

3. Tobacco using is an uncleanly habit. It dirties 
the mouth, poisons the breath, and makes one 
generally disagreeable to those who do not use 
tobacco. One look into a public smoking room, 


THE CASE AGAINST TOBACCO 


291 


or the smoking car on the train, is enough to 
condemn the use of tobacco for all who care to 
be clean and attractive. 

Questions to answer. —To what common food 
plants is tobacco related? Give an account of the first 
use made of tobacco. What is a narcotic? What is 
the principal poison found in tobacco? Why do users 
of tobacco enjoy it? What facts were shown by the 
insurance investigation about the use of tobacco and 
the length of life? In what different ways is tobacco 
known to injure the body? What facts were discov¬ 
ered by Professor Pack about the use of tobacco and 
football success? How does the use of tobacco affect 
mental work? Are there still other reasons why the 
tobacco habit should be condemned? 

Health Problems 

1. Although many seemingly well persons use tobacco, scien¬ 
tists tell us it is an enemy to health, that it lowers brain 
power and shortens life. Can a boy who wants to succeed 
afford the handicap? 

2. Try asking fifty or one hundred men smokers whether they 
would advise a boy to begin smoking. What answers do 
you get? 

3. We spend in this country far more money on tobacco than 
on education. What do you think about the wisdom of 
this? Could your school use more money for equipment, 
books, etc.? 

4. Do you believe the law should prohibit the sale of tobacco 
to minors? 


CHAPTER XXXVIII 


IN THE SICK ROOM 

Do the best we may, some one occasionally becomes 
ill in our home. The sick room then becomes the cen¬ 
ter of anxious care, and every member of the family 
tries to do his best to make everything as favorable 
as possible for recovery. 

The sick room should be quiet. —I know a boy 
whose mother is ill. Tom loves his mother and is very 
much concerned over her sickness. He longs to have 
her well, and each day he inquires whether she is not 
getting better. 

In spite of this, however, Tom is sometimes noisy 
about the house. He forgets and slams doors, or he 
drops something on the floor, or he tramps heavily 
when he walks. Nothing is farther from Tom’s inten¬ 
tions than to do anything to hurt his mother. Yet 
all of these things do hurt her, and make her recovery 
more difficult. 

It is sometimes hard for those who are well to 
realize what a difference sickness makes. The nerves 
become sensitive, and the least sudden shock causes 
pain and suffering; the mood becomes irritable, and 
292 


IN THE SICK ROOM 


293 


small pains that ordinarily would not be noticed 
disturb and annoy. Everything should be done to 
make the sick person comfortable, calm and quiet. 

Cheerfulness in the sick room. —Every one about 
the sick room should show cheerfulness, bravery and 
courage. Nothing can trouble a sick person much 
more than to have around him those who are worried, 
unhappy, or depressed in their actions. 

The conversation in the sick room should be in a 
natural, quiet tone and not in mysterious whispers. 
The sickness, trouble or death of other people should 
never form the topic of conversation in the sick room, 
as this tends to disturb and annoy one who is ill. 

Cleanliness in the sick room. —When we remem¬ 
ber that germs of all kinds thrive best in dirt, damp¬ 
ness and decay, and that germs are easily carried on 
particles of dust, we easily understand why the sick 
room should be the cleanest place of the house. The 
room should be full of fresh, moving air and should 
be flooded with sunshine. 

Furnishings for the sick room. —All furnishings 
which are not absolutely necessary for the care of the 
patient should be removed from the sick room. The 
floor should be bare, or at most have a few small rugs 
that may easily be taken out and cleaned. There 
should be no heavy curtains or hangings to gather 

dust and make a hiding place for germs. 

20 


294 PHYSIOLOGY AND HYGIENE 

No clothing should be left hanging in an adjoining 
closet or left about the room. 

Protecting from infection. —Whenever an infec¬ 
tious disease is in the house, the greatest care should 
be taken not to expose others. Even in such diseases 
as severe colds, influenza, or measles, which are not 
usually quarantined, care should still be taken. 

Separate dishes should be used for the sick, and these 
dishes should not be washed with the family supply. 
After caring for a sick person, changing the bed, or 
cleaning the room, the hands should thoroughly be 
washed in soap and hot water. If the disease is con¬ 
tagious the hands should be sterilized, after being 
washed, with alcohol or a weak solution of carbolic 
acid. 

Disinfecting a sick room. —After a patient has 
recovered from a contagious disease, one of the most 
important problems still remains. This is to disinfect 
the sick room, bedding and other articles that the 
disease may not spread to others. 

If the sickness has been one that is quarantined, the 
physician or health officer will give directions for dis¬ 
infecting. Such directions should be strictly followed. 
It is well, however, even in such diseases as measles, 
pneumonia and influenza, to disinfect after a case of 
sickness, though these diseases are not quarantined. 

One of the methods commonly used for disinfecting 
a room is to close as tightly as possible all of the cracks 


IN THE SICK ROOM 


295 


around windows and doors, and then expose in the 
room for about twenty-four hours an open dish con¬ 
taining a strong solution of formalin. But this does 
very little good. It is not nearly so efficient as a good 
scrubbing of the walls and floor with soap and water. 

All articles of clothing and bedding, which will not 
be injured by boiling, should be thoroughly boiled, as 
this will kill all the disease germs. We are not to 
forget that sunlight is one of the best germicides that 
has ever been discovered. Mattresses and such 
articles of clothing as can not be washed should be 
exposed to bright sunshine for two or three days. 

Interesting things to do. —1. Let each member 
of the class report any experience of being ill 
for several days. When you were sick were you 
annoyed by sudden noises, loud voices or other 
disturbing things which ordinarily you would 
not notice? Were you good natured or were 
you rather fretful and cross? Did you expect 
people to be good and kind to you because you 
were sick? 

2. Inquire of some member of your family or other 
person who has recently been ill whether when 
he is sick he likes talkative callers. Whether 
he likes visitors who talk about sickness, disease 
and trouble while they are visiting him. Whether 
he desires every one around the sick room to be 
cheerful and natural. 


PHYSIOLOGY AND HYGIENE 


296 

3, After inquiring of your parents, a doctor, or a 
member of your local board of health, make a 
list of all the diseases which are required by law 
to be quarantined in your city or community. 
What are the quarantine signs of these diseases? 

4. Make a list of the ways in which boys and girls 
can be helpful around the house when there is 
sickness. 

Questions to answer. —Give the case of Tom and 
his mother, who was ill. What effect does sickness 
have upon the nerves and disposition? What should 
be the manner of those who are about the sick room? 
Why should the sick room be kept especially clean? 
Describe the furnishings best adapted to the sick room 
What measures should be taken to protect others from 
contagion? Give directions as to how to disinfect 
after a case of sickness. 

Health Problems 

1. Describe the kind of room you would like if you were to be 
sick for some time; the kind of attendance you would like. 

2. One notices that hospitals always have few rugs or draperies, 
and that everything is shiny clean. Why are they furnished 
and kept in this way? 

3. What unnecessary noises are there in your city which are 
annoying to sick persons? 

4. Why should one who is sick try to keep cheerful and hopeful? 


CHAPTER XXXIX 


KEEPING COOL IN EMERGENCIES 

Did you ever stop to think what difference it makes 
whether in some kind of excitement or danger one 
does the right thing or the wrong thing? 

Several years ago in a western city, a large audience 
of children were assembled on Christmas Eve for a 
program and entertainment. It was never discovered 
who was to blame, but in the midst of the program 
some one at the back of the audience shouted fire. 

Now there was no fire nor even any smoke. Some 
one for a silly joke or some other purpose had given a 
false alarm. Immediately there was a panic and a 
wild rush for the doors. The entertainment was held 
on the second floor of the building, and the stairway 
was quickly jammed with a screaming, terrified mass. 

When the crowd was at last out and the police had 
succeeded in clearing up the pile of crushed and in¬ 
jured at the bottom of the stairs, it was found that 
more than a score of people, mostly children, had lost 
their lives. What made it seem particularly sad was 
that it was all so unnecessary. First, there was the 
foolish giving of the false alarm; and following that 
29 7 


298 PHYSIOLOGY AND HYGIENE 

was the equally foolish panic which occurred because 
the people had not learned to control themselves. 

Keeping one’s head in emergencies. —When we 
read the story of some brave deed or heroic rescue that 
has saved a life, we all feel that we would like to be 
heroes ourselves and do such things. While there are 
many different kinds of heroes, one thing seems to be 
true of all of them: they keep cool in times of danger 
or excitement. Heroes do not lose their heads and do 
foolish or unnecessary things. 

A paragraph in a newspaper before me illustrates 
this point. Two boys, one eight and the other eleven 
years of age, live in an apartment house in the city of 
Boston. One afternoon as they came home from 
school and entered the hallway, they saw smoke pour¬ 
ing out of the transom above the door of a neighboring 
apartment. Quick as a flash they rushed into the 
room. There they found two small children almost 
suffocated. They dragged them outside and down into 
the street. Then they ran and gave the fire alarm. A 
fire company quickly came and put out the fire, and 
there was no great damage done. 

Had these boys become excited and not known what 
to do, it is likely that the two children whom they 
rescued would have lost their lives. And surely our 
young friends would have lost the chance to show 
themselves heroes who can keep their heads in emer¬ 
gencies. 


KEEPING COOL IN EMERGENCIES 


299 



Saving seconds. —Often the promptness with which 
one acts may save a life. In rescuing a drowning per¬ 
son it is necessary to do something at once when he 
has been brought from 
the water. Every second 
counts. To wait for the 
arrival of the doctor or 
some other person who 
knows what to do may 
mean the difference be¬ 
tween life and death. 

The same need for 
quick action exists when 
poisons have been taken, 
when there is serious 
bleeding from a cut or 
wound, or when some one 
has been suffocated by 
breathing gas. 


Knowing the right 

thing to do . —I f one Do not use candles on a Christmas tree. 

is to keep calm and work Man v lives have been lost b v Christ “ 
r . . mas tree fires 

fast in emergencies he 

must first of all know just what to do. When the 
emergency comes it is too late to learn, for there is 
no time. 

No boy or girl can tell when the chance may come 
to save a life by using knowledge and skill. Let each 







300 


PHYSIOLOGY AND HYGIENE 


of us ask ourselves the question: Would I know what 
to do in some of the more common emergencies? 
Would I know how to treat a person who has been 
rescued from drowning? Would I know what to do 
if a companion had broken his leg? Would I know 
what to do in a case of poisoning? Would I know 
what to do in case of severe bleeding? 

Skill through practise. — I suppose many of those 
who study this lesson are in schools where there is 
regular fire drill. You are taught to obey signals, to 
march, and perhaps to use the fire-escapes. You go 
through these drills time after time, although no fire 
has ever occurred in your building. 

In similar way soldiers are drilled day after day 
and week after week in marching, handling their fire¬ 
arms, and doing everything else that a soldier has to 
do. This drill is carried on until the soldier’s movements 
become almost second nature to him, so that he can 
do them without thinking. 

Drill is the only way to make sure of calmness and 
skill in times of emergency or danger. It is for this 
reason that Boy Scouts and Girl Scouts are given 
practical training in what to do in all the common 
emergencies. 

In the lesson which follows suggestions will be given 
for training and practise which will enable you to know 
what to do when the chance comes to show yourself 
a hero in some emergency. 


KEEPING COOL IN EMERGENCIES 


301 


Interesting things to do. —1. Let each member 
of the class write or tell the story of some acci¬ 
dent or exciting incident with which he was 
connected. Did you know what to do? Did 
you keep cool? Did you do the right thing? 
What should you have done differently? 

2. Let each member of the class tell the bravest 
thing you ever saw done. The narrowest escape 
you ever saw any one have. Did the person 
concerned keep cool and act wisely in each case? 

Questions to answer. —Tell the story of the fire 
alarm at the Christmas exercises. What two great 
mistakes were made on this occasion? What is one of 
the first qualities that one should have in a case of 
emergency? Give the case showing how the cool- 
headedness of two boys saved the children from burn¬ 
ing to death. Why is it necessary to act promptly in 
many cases of emergency? Why is it necessary that 
we should learn beforehand what to do in the case of 
certain emergencies? Why should we practise doing 
certain of the things beforehand which may need to 
be done in emergencies? 

Health Problems 

1. It has been found that Scouts are usually cool-headed in 
emergencies. How is this to be accounted for? 

2 . At a place where a house took fire, a woman threw a mirror 
out of a second story window and carried a mattress down 
the stairs. Account for her strange action. 


CHAPTER XL 


WHAT TO DO IN EMERGENCIES 

It is not enough that we should merely learn what 
to do in emergencies. If you are to be able to use 
your knowledge when the emergency comes, you 
must actually do over and over again in practise the 
things to be done in the emergency until you can do 
them quickly and skilfully without excitement. 

This lesson therefore tells you how to do certain 
things that should be done in emergencies. 

Drowning. —Every American boy and girl should 
know how to swim. This is worth while, first of all, 
for the pleasure it gives. But aside from that we ought 
to know how to swim in order to be able to save our 
own lives or the lives of others in case of emergencies 
in water. 

A drowning person when taken from the water is 
not breathing, and the failure to take air into the lungs 
has partially or even wholly stopped the action of the 
heart. The first thing necessary, therefore, is to get 
the breathing and the circulation started again. 

To do this, place the patient flat on his stomach. 
Have his head turned to one side, and lower than the 
302 



WHAT TO DO IN EMERGENCIES 303 

rest of his body so that the water can drain from the 
lungs. Take a position like that shown in the picture, 
with the thumbs nearly meeting on the small of the 
patient’s back, and with the fingers clasping the sides 


Producing artificial breathing in case of drowning 

at the small ribs. Now swing your body forward, 
pressing with your weight and the grip of your hands 
on the small of the back and the side. Then immedi¬ 
ately swing your body backward releasing the pressure. 
Do this regularly about twelve times a minute, and 







304 


PHYSIOLOGY AND HYGIENE 


keep it up! Do not get discouraged. Life has been 
known to return after more than an hour of such 
work during which no sign of consciousness had been 
shown. 

If other help is at hand, some one should at once be 
sent for dry blankets, while others are rubbing the 
arms and legs to help start the circulation. While 
recovering the patient should have hot water bottles 
at the feet and be kept warmly covered. 

Carrying an injured person. —A person who has 
been seriously injured or has broken bones should 
ordinarily not be carried. The best thing to do in such 
a case is to straighten the injured person out in a com¬ 
fortable position, cover with a blanket or with extra 
clothing, and immediately send for help. 

Two different kinds of seats are easily made for 
carrying the injured. One is formed by tying the cor¬ 
ners of a handkerchief together, making out of it a 
ring. Each of the two who are to carry then takes 
hold of the ring, the patient resting on the seat between 
them. 

A second method, if a blanket is to be had, is to tie 
together the diagonally opposite corners. Those who 
are to do the carrying place the ring over their heads. 
This method leaves the hands free to help support the 
patient. 

If a blanket is at hand a stretcher may be quickly 
made by rolling each of the edges around two sticks 


WHAT TO DO IN EMERGENCIES 


305 


tightly enough that it will not slip. If no blanket is 
available a stretcher may be made by taking two 
coats, buttoning them, and then passing poles through 
the bodies of the coats. 



Many destructive fires are started by children setting bon¬ 
fires in dangerous places. Never start a fire near houses, 
barns, wooden fences or other inflammable material 

When clothing takes fire. —If we remember two 
things they will help us understand what to do in 
case our clothing catches fire: 

(1) Fire will continue to burn only when it has 


air. 





PHYSIOLOGY AND HYGIENE 


306 

(2) Flames always have a tendency to leap upward 
and not downward. 

A person whose clothing is on fire should never 
start to run. This only fans the flames by giving 
them air. The thing to do is to drop instantly to the 
floor and roll over and over; or better still to roll up 
in a rug or in bed covering. In this way the flames 
are smothered for want of air and the fire put out. 

The first thing necessary in treating serious burns 
is to keep the air away from them. If a large portion 
of the body has been burned, there is no better way 
than to put the patient into a tub of warm water, 
clothes and all, until the doctor arrives. If the hand 
has been burned, plunge it in water and keep it there, 
even for hours until the pain lessens. 

When something gets into the eye. —The first 
thing we usually think of doing when a cinder or an 
insect gets into the eye is to begin rubbing it. This 
is the very worst thing that could be done; for rub¬ 
bing will irritate the tender lining of the lid, and may 
make the particle imbed itself still more deeply. 

The skin of the eyelid may be caught between the 
finger and the thumb and the lid pulled downward or 
away from the eye and allowed to snap gently back. 
This will sometimes loosen the stray particle and then 
the tears will wash it out. 

The corner of a handkerchief moistened in clean 
water may be used without injury to wipe the particle 


WHAT TO DO IN EMERGENCIES 


307 


out. If this does not work, It Is best to sit down in a 
chair and allow some one standing behind us to turn 
the lid back so that the particle can be found and 
removed. 

When poison has been swallowed. —In the case 
of most poisonfe, the necessary thing to do is to produce 
vomiting so as to remove the poison from the stomach. 
A good emetic is mustard mixed with warm water, a 
teaspoonful to the pint. If mustard is not at hand put 
salt in the water. If neither can be had do not wait 
to send or hunt for them, but give the patient warm 
water. Be sure that he keeps drinking until he vomits. 
Remember that vomiting is the main thing, and that 
every second counts. If no warm water is at hand it 
is even well to give a drink of cold water while water 
is being warmed. Tickling the back of the mouth with 
the tip of the finger will help to produce vomiting. 

The whites of eggs are safe to give in any kind of 
poisoning. The whites of four or five, or even six, 
eggs may be stirred into a quart of water and the 
person made to drink as much of this as he can. 

If an alkali or an acid poison has been taken, vomit¬ 
ing should not be produced. Alkalies and acids have 
the power to neutralize, or kill the effects of, each 
other. A person who has taken an alkali poison, like 
lye, or ammonia, may be given vinegar, which is acid ; 
one who has taken any acid may be given thick lime 
water or ordinary baking soda, both of which are alkali. 


3°8 


PHYSIOLOGY AND HYGIENE 


Common poisons and their treatment.— 


Alcohol, whisky.Emetic, strong coffee 

Arsenic, rat poison.Emetic, whites of eggs or milk 

Gasoline... Emetic 

Camphor.Emetic, coffee, warmth 

Chloroform.Air, artificial respiration, coffee 

Matches.Emetic, whites of eggs, Epsom salts 

Morphine, soothing syrup .Emetic, artificial respiration 

Turpentine..Emetic, keep awake 

Alkalies— 

Ammonia 1 

Lye f.Vinegar, oil, milk 

Potash J 

Acids— 

Sulphuric \ .Strong lime water or soda, 

Hydrochloric / whites of eggs 

Lead poisons.Emetic, Epsom salts 

Tobacco.Coffee 

Strychnine. . Emetic, whites of eggs, artificial respiration 
Mushrooms.Emetic, castor oil 


Plants that poison the skin. —Many persons are 
particularly sensitive to poison ivy, which is to be 
found growing almost everywhere. Of course the 
safest plan is to keep away from poison ivy; but many 
persons can not tell the difference between pcison ivy 
and the harmless kind. Poison ivy has three leaves 
and yellowish green berries. The harmless kinds have 
five leaves and red berries . 














WHAT TO DO IN EMERGENCIES 


309 


The best remedy so far known for curing poison ivy 
trouble is simply to wash the skin thoroughly with 
soap and water. This is a safe thing to do whenever 
we come in from the woods, and is likely to save us 
much trouble if our skin is sensitive to plant poisons. 

Swamp sumach is a poisonous plant found in thickets 
in many parts of the United States. It contains the 
same poison as that found in poison ivy, but the poison 
is stronger and more severe in its effects. The soap 
and water treatment is the best remedy. The poison¬ 
ous swamp sumach has white berries , the common, 
harmless sumach has red berries. 

Poisonous stings. —The sting of bees, wasps, 
yellow-jackets, hornets, and even of mosquitoes con¬ 
tains poison. The poison is driven into the skin by 
means of a sharp stinger. The stinger of the bee is 
barbed so that he can not pull it out, and so when he 
stings you he loses his stinger. The stinger should be 
removed with a pair of tweezers. 

The sting of such insects is acid and so calls for an 
alkali in treatment. Common cooking soda is good 
for the sting of nearly all insects. If this is not avail¬ 
able, a little moistened earth placed over the sting 
will usually cure the pain. 

Bleeding at the nose. —Bleeding at the nose will 
ordinarily check itself in a few minutes. Keep the 

head erect, as this permits less blood to be sent to the 

21 


3io 


PHYSIOLOGY AND HYGIENE 


nose. Ice, or cloths wrung out of cold water, may be 
placed at the back of the neck and over the head at 
the bridge of the nose. Pinching the nostrils together 
tightly will help hold the blood back until the bleeding 
naturally stops. 

When bleeding of the nose continues for a long time, 
the doctor sometimes packs the nostril tight with 
cotton. One should not blow the nose nor cough 
when the nose is bleeding, as this makes the blood 
flow faster. 

Bandaging. —Bandaging is often necessary to pro¬ 
tect a wound from dirt or from injury. Sprains and 
bruises should be bandaged to protect the injured part 
and to keep the blood from settling in the broken 
capillaries. 

The roller bandage is commonly used by physicians 
and nurses where the bandaging must be tight. This 
form of bandage is rather hard to apply, and requires 
a long strip of cloth rolled up in a firm roll. 

The triangular bandage is made by cutting diagon¬ 
ally a square piece of white cloth. Cheesecloth makes 
excellent bandages. The size of the bandage depends 
on where it is to be applied. Before applying a band¬ 
age to a cut or break in the skin the cloth should, if 
possible, be sterilized by wringing it out of boiling 
water or by baking it in a hot oven. Bandages should 
be tied with a “square” knot, as this will not slip and 
is easily untied. 


WHAT TO DO IN EMERGENCIES 


311 


For small cuts and wounds, torn nails and the like, 
surgeon's plaster , or adhesive tape, should be used. A 
small piece of sterilized cloth may first be put over a 
sore, and the cloth held in place by the plaster. Ten¬ 
cent rolls of surgeon’s plaster can be bought at drug 
stores. 

Interesting things to do. —1. Use a classmate as 
a patient and show how to start artificial respi¬ 
ration in a person rescued from drowning. 

2. Prepare a ring seat and a blanket seat and then 
show how to carry an injured comrade. Also 
show how to make a stretcher out of two poles 
and a blanket, or with the poles and coats. 
Have some one time the different members of 
the class to see who can prepare each of these 
pieces of apparatus in the shortest time. 

3. Imagine that your own clothing has caught fire, 
and show how to proceed in putting it out. 
Imagine a companion’s clothing is on fire and 
show how to proceed. 

4. Show how to remove a cinder from your eye, 

(1) by pulling down the lid and letting it go, 

(2) by using the corner of your handkerchief 
before a mirror. 

5. Study the square knot and learn to tie it quickly. 
Then show how to prepare and apply a bandage 
to the hand; to the head; to the foot; how to 
make and apply a sling for the arm. 


312 


PHYSIOLOGY AND HYGIENE 


Questions to answer. —Why should boys and girls 
learn how to swim? What is the condition of the lungs 
and heart of a person rescued from drowning? Give 
full directions for bringing about artificial respiration. 
What care should be given a person rescued from the 
water after breathing begins? Explain several differ¬ 
ent ways in which an injured person may be carried. 
Tell what to do when the clothing has taken fire. 
Give directions for removing a cinder from the eye. 
Give the treatment for each of several different kinds 
of poison. What is the treatment for poison? What 
is the treatment for poison ivy or other poisonous 
plants? Tell how to treat the sting of a poisonous 
insect. What are the two kinds of bandages most 
used? Tell how to prepare and apply the different 
bandages. 

Health Problems 

1. Give an account of the most exciting or the most serious 
emergency you were ever in. Did you and did others do 
the right thing? 

2. Gather examples of emergencies in which the wrong thing 
was done, or in which no one seemed to know what to do. 
Decide in each case what should have been done. 

3. Sometimes in an accident, one must act “without waiting 
to think.” How can he prepare for this kind of action and 
be sure he will do the right thing? 


CHAPTER XLI 


SAFETY FIRST 

No one likes the coward. Every boy and girl wants 
to be brave, and to have the spirit of daring and 
adventure. We should even be willing to show our 
courage by taking risks for others in times of danger. 

But one should never be fool-hardy nor take un¬ 
necessary risks. The truly brave man risks danger or 
death only when he can gain some necessary end by 
it. The one who risks danger just to show his daring 
is either vain or he lacks sense and judgment. 

Jumping freight trains. —One of the most foolish 
and unnecessary risks sometimes taken by boys is 
jumping on moving freight trains or climbing over 
freight cars in the switching yards. 

All railway companies have regulations against 
persons riding on freight cars or trespassing in the 
freight yards where cars are being moved. Yet every 
year there are many tragic accidents because boys 
disobey these regulations. This morning as I looked 
out of the window I saw a fine-looking young fellow 
going down the street with but one leg, a crutch doing 
duty for the other. Two years ago this boy and three 
313 


314 PHYSIOLOGY AND HYGIENE 

others undertook to steal a ride on a freight train. 
An accident happened to Fred, and he will have to go 
through life a cripple. 

Accidents from street-cars. —Every year shows 

a long list of accidents to people from street-cars. 
These accidents are mainly from two sources: People 
are hurt in getting on or off the car, or else they are 
run over by passing in front of cars. There is just 
one way of getting on or off a street-car properly. 
That is, (i) after the car has stopped; and (2) with 
the face toward the direction in which the car is moving. 
If the car suddenly starts this enables one to move 
forward with its motion in place of falling backward. 

Most of the serious street-car accidents, however, 
come from people being run over by moving cars. 
This usually happens from some one trying to dodge 
across ahead of a car, and either misjudging the dis¬ 
tance or else being struck by a car coming from the 
opposite direction on another track. One should 
never cross a street-car track without making sure. 

Dodging automobiles. —Nearly every driver of an 
automobile is very careful not to run over people on 
the street. Yet occasionally there is a careless driver 
who disobeys driving regulations, and injures or kills 
some one in his way. 

One should have his best attention about him when 
he is crossing streets or roadways upon which auto- 


SAFETY FIRST 


315 


mobiles are passing. A large proportion of automobile 
accidents come from children playing on the streets, 
and getting so interested in their game that they 
forget to notice the automobiles. 

Only yesterday I saw a driver narrowly avoid run¬ 
ning over a small girl by almost driving his car into 
a street-car. A group of children were playing in the 
street near the sidewalk when suddenly this girl, look¬ 
ing back at her companions and not pausing to notice 
whether the street was clear, darted toward the mid¬ 
dle of the street and straight into the pathway of the 
automobile. Her first mistake was playing in the 
street where automobiles were passing ^yhen there 
were plenty of other places to play. Her second 
mistake was in running out into the street without 
first looking to see whether the pathway was clear. 

Driving automobiles. —Some states do not permit 
those under sixteen years of age to drive an auto¬ 
mobile, nor allow one to drive without a license showing 
that he knows how to operate a car. In many places, 
however, boys and girls much younger than sixteen 
are found driving cars. 

It is no great trouble to learn to drive a car safely 
if one will have for his rule “safety first* 1 at all times. 
The collisions and tip-overs and other accidents in 
which cars are smashed up usually come either from 
speeding or from disobeying the driving rules. 

One who drives an automobile should remember 


316 PHYSIOLOGY AND HYGIENE 

that he not only has in his keeping his own safety, 
but also the safety of others who may be driving upon 
the roadway. No person should drive a car who does 
not understand his car, and know how to operate it. 
Nor should he be trusted with a car unless he is willing 
to drive at reasonable speed, and obey the rules of the 
road. 

Handling firearms, —The paper this morning tells 
of another shooting tragedy which happened because 
a boy “didn’t know that it was loaded.” Every year 
many people lose their lives by being accidentally 
shot by those who either do not know how to handle 
a gun, or else are too careless to be safe in using one. 

There are two rules which every person who handles 
a gun should rigidly follow: 

(1) Never point a gun at another person even in 
fun, though you may be entirely sure that the 
gun is not loaded. 

(2) Always carry a gun with the muzzle pointing 
forward and downward. 

Questions to answer. —Explain the difference be¬ 
tween true bravery and foolish daring. What should 
be the rule about jumping on freight trains, or climb¬ 
ing over cars? Give directions for avoiding accidents 
by street-cars. Give directions for avoiding accidents 
by automobiles. What should be our rule in handling 
firearms?___In carrying a gun? t 


GLOSSARY 


KEY TO PRONUNCIATION 

a as in fate, senate, fat, arm, all, ask, what, care, 
e 44 mete, event, met, her, there, obey, 
ee “ feet. 

i 44 Tee, Idea, Tt, sir, machine, 
o 44 old, obey, not, move, wolf, son, horse, work, 
oo “ food, foot. 

u “ use, unite, up, fur, rule, pull, 
y 44 fly, myself, baby, myrrh, 
au 44 author. 

aw 44 saw. ew as in new. oi as in boil, 

oy 44 boy. ou 44 out. ow 44 cow. 

ABDOMEN (ab do'men)—The large cavity at the lower part, of the 
trunk which contains the digestive tract and other organs. 
AMOEBA (a me'ba)—An animal too small to be seen by the eye, and 
consisting of but a single cell. 

ANTISEPTIC (an tT sep'tTk)—A substance used in wounds and sores for 
the purpose of killing disease germs. 

ANTITOXIN (an tT tok'sTn)—Any substance that will destroy a dis* 
ease poison in the body. 

ARTHRITIS (ar thrl'tis)—The scientific name for rheumatism, involv¬ 
ing joints. 

BACTERIA (bak te'rT a)—Very small, invisible plants consisting of but 
one cell. 

BICEPS (bT'seps)—The flexor muscle found at the front of the upper arm. 
BRONCHI (bron'ki)—The branches of the trachea through which air 
reaches the air cells of the lungs. 

CALORY (kal'o rT)—The unit for measuring the amount of food the, 
body requires (also a measure for heat). 

CAPILLARIES (kap'T la riz) — Small blood-vessels connecting the 
arteries and veins. 

CARBOHYDRATES (kar bo hi'drats)—Energy-producing foods. 

317 





3 18 GLOSSARY—Continued 

CARTILAGE (kar'tT laj)—A tough, rubber-like substance found be¬ 
tween the bones at movable joints. 

CEREBRUM (ser'e brum)—The large, upper part of the brain. 

CHRONIC (kronlk)—Continuing for a long time, as a disease that 
gradually gets worse. 

COAGULATION (ko ag u la'shim)—The hardening or clotting of the 
blood when outside the body. 

COCHLEA (kok'le a)—A snailshell-like part of the inner ear. 

CORPUSCLES (ko^'pus ’Iz)—Small bodies found floating in the plasma 
of the blood. 

DIAPHRAGM (di'a fram)—The muscular floor or partition between 
the chest cavity and the abdomen. 

DIFFUSION (di fu'zhiin)—The process by which a liquid or a gas 
passes through animal tissue. 

DYNAMOMETER (dT na mom'e ter)—An instrument for measuring 
the strength of the grip of the hand. 

EMETIC (e met'ik)—A substance given to produce vomiting. 

EPIDEMIC (epTdem'ik)—An attack of disease which affects a large 
number of people. 

ESOPHAGUS (e sof'a gus)—The part of the digestive tract leading 
from the mouth to the stomach. 

FIBRIN (fl'brTn)—That part of the blood which causes thickening or 
clotting of blood when outside the body. 

FORMALIN (for'ma lm)—A strong poison used to destroy disease 
germs or other microbes. 

GERMICIDE (jur'mT sid)—Any substance used to kill germs. 

GOITER (goiter)—A disease which causes an enlargement of the 
thyroid gland. 

INFECTION (in fek'shun)—Any substance or poison which will cause 
or communicate disease; or the state of being diseased. 

LYMPHATICS .(lim fat'rks)—The system of vessels which convey the 
lymph in its circulation. 

MASSAGE ^ (ma sazh')—A method of treating the flesh by rubbing, 
stroking, kneading, etc. 

MENINGITIS (men In ji'tis) —A serious disease which attacks the 
wrapping coats of the brain and spinal cord. 

MICROBES (mT'krobs)—Very small animals or plants consisting of a 
single cell. 

MOLECULE (mol/e kul)—One of the smallest divisions of matter. 


GLOSSARY—Concluded 


319 

NARCOTIC (nar kot'ik)—A drug which stupefies or quiets the nerves 
and the mind. 

NICOTINE (mk'o trn)—A poison found in tobacco. 

PASTEURIZE (pas'terlz)—The process of killing bacteria in milk by 
heating it just enough to kill the disease germs. 

PERICARDIUM (per 1 kar di urn)—The sack or bag which surrounds 
the heart. 

PERIOSTEUM (per T os te um)—A tissue which covers the bones. 

PLASMA (plaz'ma)—The liquid part of the blood. 

PLEURA (ploo'ra)—The w r rapping or covering of the lungs. 

'PROTEIN (pro'tem)—The part of our foods which goes to rebuild 
or cause the growth of cells. 

PROTOPLASM (pro'to plazm)—The living substance of which the 
body’s cells are chiefly composed. 

PROTOZOA (pro to zo'a)—Very small one-celled animals. 

PYLORUS (pi lo'rus)—A muscular gateway between the stomach and 
the small intestine. 

RESPIRATION (res p? ra'shun)—The process of breathing. 

RETINA (retT na)—The sensitive nerve coat at the back of the eye. 

SALIVARY GLANDS (sal'i va r!)—Glands located in each jaw, and 
which supply the saliva. 

SPIROMETER (spt rom'e ter)—An instrument for measuring the air 
capacity of the lungs. 

STERILIZE (ster'i ITz)—To treat in such a way as to kill the germs on 
any article or in a wound or sore. 

TENDONS (ten'dunz)—Inelastic cords which tie the muscles to the bones. 

THORAX (tho'raks)—The upper part of the chest cavity which con¬ 
tains the heart and the lungs. 

THYMUS (thl'mus)—A gland located behind the breast bone. 

THYROID (thT'roid)—A gland located in the throat. 

TUBERCLE BACILLUS (tu'ber kl ba sil'us)—The germ which causes 
tuberculosis. 

VACCINE (vak'sTn)—The matter, or virus, used to vaccinate for 
smallpox; also dead bodies of germs of certain diseases, injected 
to immunize the person against that disease. 

VILLI (vTl'I)—Small, hair-like projections lining the air-passages and 
acting to expel dust or other foreign particles. 

VITAMINS (vTta minz)- Substances found in uncooked foods, and 
necessary to health. 


INDEX 


Air, 118 

Alcohol, ch. on, 277 
and the brain, 71 
the case against, 277 
and disease, 222 
and the glands, 186 
and the nerves, 53 
Antitoxins, in the blood, 217 
Arteries, 93 
Athletic Leagues, 1 
Athletic Records, 1 
Bandaging, 310 
Bleeding, from cuts, 86 
from the nose, 309 
Blood, ch. on, 82 
circulation of, 89 
composition of, 83 
and lymph, 100 
Body, the, in action, 1 
ch. on, 191 
control of, 148 
Bones, ch. on, 26 
joints and, 36 
and posture, 31 
structure of, 27 

Brain, the, 55 

Breathing, ch. on, 107 
habits of, 111 
mechanism of, 109 
shallow and deep, 111 


Burns, 306 
Capillaries, blood, 95 
Carbohydrates, 134 
Cartilage, 37 

Cells, air, 117 
ch. on, 62 

things that injure, 64 
Character, 73 
Chickenpox, 251 
Chyle, 167 

Clothing, and breathing, 113 

Community health cooperation 
232 

health score card, 238 
home and, 233 
school and, 235 

Cord, the spinal, 57 

Corns, 46 

Corpuscles, blood, kinds of, 83 
work of red, 84 
work of white, 216 

Diaphragm, the, 109 

Digestion, ch. on, 164 

things that hinder, 168 

Diphtheria, 250 



INDEX—Continued 


321 


Disease, the body’s defenses 
against, 215 
“carriers” of, 210 
rats and mice and, 213 
germs and, 198 
immunity against, 219 
resistance to, 220 

Disposition, 71 

Drowning, 302 

Ear, the, ch. on, 269 
care of, 272, 274 
defects of, 273 

Emergencies, ch. on, 297 

rules for meeting, 298, 302 

Experiments, on the blood, 86 
on bone tissues, 34 
on breathing, 107, 114 
in preventing coughing, 204 
on the circulation, 98 
on diffusion, 100 
on the ear, 275 
on the eye, 259, 266 
with the feet, 46 
on fatigue, 80 
on the glands, 189 
on the lungs, 123 
on muscle tissue, 8 
on the nerves, 53, 60 
on the senses, 259 
on developing skill, 24 

Eye, the, ch. on, 261 
care of, 266 

removing particles from, 306 
structure of, 262 
tests for, 265 

Face, the expression of, 14 


Fatigue, ch. on, 75 
removal of, 76 
poisons caused by, 75 

Fats, as foods, 134 

Fibrin, 87 

Fire, prevention of, 305 

Food, and bodily energy, 126 
cooking of, 149 
nature’s preparation of, 125 
kinds required, 133 
measuring values of, 141 
tables of values of, 139, 144, 
145, 146 

Foot, the, ch. on, 41 
curing weak feet, 45 
tests for flat, 42 

Germicides, 216 

Germs, disease, 198 

how distributed, 201 
in milk and water, 208, 209 

Glands, ch. on, 184 
lymphatic, 104 

Habits, good breathing, 112 
muscle, 16 
nerve, 59 

Heart, the, structure of, 91 
effects of tobacco on, 65 

Hookworm, 251 

Joints, ch. on, 36 
kinds of, 36 

Kidneys, the, 187 

Ligaments, 38 

Liver, the, 185 


322 INDEX— 

Lungs, the, ch. on, 116 
and dust, 119 
elasticity of, 109 
power of, 121 
work of, 116 

Lymph, 100 

Lymphatics, 104 

Massage, 77 

Measles, 247 

Mice, 213 

Mumps, 250 

Muscles, nature of, 3 

training and care of, 11, 18 
controlled by nerves, 48 

Nerves, ch. on, 48 
classes of, 56 
functions of, 50 
habits of, 59 

Nervous System, 68 

Plasma, the, 83 

Plants, as food, 128 

Poisons, antidotes for, 308 
treatment for skin, 309 

Posture and bone shapes, 31 
and breathing, 113 
correcting wrong, 32 
habits of, 14 

Protein, as food, 13* 

Pyorrhea, 179 


Continued 

Rats, 213 

Respiration, 107 

“Safety First,” 313 

Salivary Glands, 187 

Scarlet fever, 248 

Score card, community health, 
238 

Senses, the, ch. on, 254 
organs of, 256 

Sick Room, the, ch. on, 292 
care of, 294 

Skill, training to. muscular, 21 
and the nerves, 50 

Sleep, 78 

Spitting, 202 

Teeth, ch. on, 172 
care of, 180 
decay of, 177 
structure of, 175 
uses of, 173 

Tendons, 4 

Thymus Gland, the, 188 

Thyroid Gland, the, 188 

Tobacco, ch. on, 285 

the case against, 286 
and the nerves, 54 

Tuberculosis, ch. on, 241 
cure of, 244 
prevention of, 245 
symptoms of, 243 



INDEX—Concluded 


323 


Vaccination, ch. on, 225 
against diphtheria, 229 
against smallpox, 227 
against typhoid, 228 

Veins, the* 94 


Water, ch. on, 155 

the body’s need of, 156 
disease dangers from, 161 
aources of drinking, 160 

Whooping cough, 249 
Worry, and fatigue, 78 


W.B.C. 































